Mobile-Friendly Firefox Customizations for Librem 5

[ASwyD2]

@tfardet

do you maintain by any chance a repo where one could download the files directly? (it would be more convenient to find and get them than a forum post and it would enable to keep track of the changes with tags per FF version, etc)

If you read higher @Emma fields your question.

[Lliure]

@tfardet

having these as variants of the firefox-esr-mobile-config (e.g. a firefox-esr-true-mobile-config, etc) with the Purism folks? That could enable more people to benefit from your hard work

I’m sure they’re happy to review merge requests against PureOS’s firefox-esr-mobile-config package.

[Rhodez-x]

Maybe I miss an important detail. I have the firefox-esr-mobile-config installed at the latest version.
However I’m pretty sure that my Firefox is not using it. Is there something active I need to do?

Edit: Seems that I missed the very first thing in the OP
I’ll try it out later today.

[tfardet]

If you read higher @Emma fields your question.

Ah, yes, I found a post about Codeberg, then maybe Sourcehut would suit you @Emma (I you want to give it a try), it does not require javascript and does not use any captcha, tracking, or anything really.

[Emma]

@tfardet

Wow, thanks a lot for your work on making FF work better on mobile!

Thank you for the appreciation!

@tfardet

• do you maintain by any chance a repo where one could download the files directly? (it would be more convenient to find and get them than a forum post and it would enable to keep track of the changes with tags per FF version, etc)

While I don’t have a repo and currently don’t want one, I do have a kbin account and am considering posting updates and uploading files there will be posting updates there. So follow me for updates:

Overview - user0 - Fedia

This kbin instance is also the new home of the FirefoxCSS community from reddit:

Firefox Customs - Fedia

@tfardet

• more generally, did you ever discuss the possibility of having these as variants of the firefox-esr-mobile-config (e.g. a firefox-esr-true-mobile-config, etc) with the Purism folks? That could enable more people to benefit from your hard work

I have not discussed anything with Purism directly, but I am posting FOSS code to their forum and give them explicit permission to take any and all of my work here and package it into PureOS so that everyone may benefit.

[Emma]

October 2023 Halloween Update:

Just in time for Halloween! Dress up the Firefox app on your Librem 5 to look like Firefox for Android!

Update Summary

• Added userContent.css (fenix) to fix Firefox about pages to be better fit for Librem 5 as well as a color theme to match Firefox for Android, code-named Fenix.

• Added fenix_colors.css for a color theme to match Firefox for Android, (Fenix). If you do not want the Private Browsing Mode theme for the URL Bar and Nav Bar, comment out that section of code at the bottom of the file.

• Added fenix.css as an alternative to true_mobile_mode.css that more closely resembles Firefox for Android (Fenix).

• Added extensions_menu.css to fix the Unified Extensions Menu.

• Added dynamic_popups.css and several variations so that extensions expand into a big enough popup which also supports horizontal scrolling. Works best with true_mobile_mode.css or fenix.css.

• Added alt-browser-alt.css to be used with true_mobile_mode.css or fenix.css instead of browser.css. It can also be used with other styles like alt-single_tab_mode-alt.css to have the Tab Bar at the top of the screen and the Nav Bar at the bottom.

• Added single_tab_mode-alt.css, true_mobile_mode-alt.css, and fenix-alt.css, to be used without alt-browser-alt.css or browser.css in order to have the Nav Bar at the top of the screen.

• Added true_mobile_landscape.css and true_mobile_landscape-alt.css to have a nice landscape mode that maximizes usable space and fixes flickering popups.

• Added fenix_fox.css to have a single standalone userChrome file containing all necessary code except fenix_colors.css. You can add dynamic_popups.css or another variation. fenix_fox-alt.css is the version that has the Nav Bar at the top of the screen. You will still need userContent.css (fenix).

• Added fenix_one.css to have a single standalone userChrome file containing all necessary code, including fenix_colors.css. If you do not want the Private Browsing Mode theme for the URL Bar and Nav Bar, comment out that section of code at the bottom of the file. You can add dynamic_popups.css or another variation. fenix_one-alt.css is the version that has the Nav Bar at the top of the screen. You will still need userContent.css (fenix).

• Added variables into many files so that they work in “Normal” and “Touch” density modes.

• New CSS files:

  • alt-browser-alt.css
  • extensions_menu.css
  • single_tab_mode-alt.css
  • alt-single_tab_mode-alt.css
  • true_mobile_landscape-alt.css
  • true_mobile_landscape.css
  • true_mobile_mode-alt.css
  • dynamic_popups.css
  • dynamic_popups_plus.css
  • dynamic_popups_max.css
  • dynamic_popups_pro.css
  • dynamic_popups_pro_max.css
  • userContent.css (fenix)
  • fenix_colors.css
  • fenix-alt.css
  • fenix.css
  • fenix_fox-alt.css
  • fenix_fox.css
  • fenix_one-alt.css
  • fenix_one.css

• Updated CSS files:

  • appMenu.css
  • browser.css
  • editBookmarkPanel.css
  • popups.css
  • tabmenu.css
  • iconized_main_menu.css
  • round_ui_items.css
  • numbered_tabs.css
  • tab_counter.css
  • custom_rules.css
  • single_tab_mode.css
  • new-tab-button.css
  • true_mobile_mode.css

Important:

• The final post from this multi-post update is the Styles & Screenshots (post 61).

• All of my most recent code is in the posts from this update (posts 55-61); ignore earlier posts.

• For a summary of the updates that were applied to the October 2023 Halloween Update, see the Final Updates (post 70).

• Remember that you don’t need to save all of the files in this thread; you only need the ones for the styles that you intend to use.

About the files

• browser.css places Tab Bar & Nav Bar at bottom of screen.

• alt-browser-alt.css places Tab Bar at top of screen and Nav Bar at bottom of screen.

• Files that end with alt are to be used without any browser file, to keep Tab Bar & Nav Bar at top of screen:

  • single_tab_mode-alt.css
  • true_mobile_mode-alt.css
  • fenix-alt.css

• The following files are to be used with alt-browser-alt.css, to place Tab Bar at top of screen and Nav Bar at bottom of screen:

  • alt-single_tab_mode-alt.css
  • true_mobile_mode.css
  • fenix.css

• true_mobile and fenix files hide Tab Bar.

• The following files can be renamed to userChrome.css, if you prefer having a single userChrome file:

  • fenix_fox-alt.css
  • fenix_fox.css
  • fenix_one-alt.css
  • fenix_one.css

• Whichever userChrome file or files you decide to use, you will still need a userContent.css file.

This thread is best viewed with javascript disabled in your browser.

Code:

mobile-config-firefox by postmarketOS (modified by user0):

appMenu.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* Spawn the menu above the navigation bar (now that we've moved it to the
     * bottom). Without this, it still spawns above, but only with a small
     * height. This is due to the position="bottomcenter topright" attribute in
     * the HTML, which we can't override via CSS. */
    #appMenu-popup {
        /*margin-top: -390px !important;*/
        padding-left: 10px !important;
        padding-right: 10px !important;
        /*height: 310px;*/
        /*max-height: 310px;*/
        height: 330px;
        max-height: 330px;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        /*height: 300px !important;*/
        /*max-height: 300px !important;*/
        height: 318px !important;
        max-height: 318px !important;
    }
    #appMenu-multiView box.panel-viewstack:first-child {
        /* Use the whole space in the menu, instead of slowly increasing the
         * height via animation. This animation is broken anyway due to the
         * above menu size hack */
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }

    /* Menu content
     * - configure it to have most important functions for mobile
     *   on one page, without scrolling. (Scrolling was only possible with the
     *   scrollbar on the right anyway, which is awkward when expecting to be
     *   able to scroll with fingers.)
     * - submenus are hidden, because attempting to scroll inside them with the
     *   finger causes firefox to segfault. This is likely due to the menu
     *   positioning hack above, looks like FF can't determine the height
     *   properly. Help with fixing this is appreciated, the bookmarks and
     *   history submenus would be useful. However even without the submenus,
     *   the history and saved bookmarks can at least be accessed conveniently
     *   through the navigation search.
     * - fullscreen is hidden: not available in FF for android either, the
     *   screen is almost used completely already, causes problems with UIs
     *   that don't expect apps to go fullscreen (i.e. in Phosh, as soon as
     *   the on screen keyboard is triggered, the top and bottom bars of Phosh
     *   are over the FF in fullscreen) */
    #appMenu-fxa-status2, /* FF login */
    #appMenu-fxa-separator, /* FF login */
    /*#appMenu-new-window-button2,*/
    #appMenu-protonMainView toolbarseparator, /* all separators */
    /*#appMenu-save-file-button2, /* Save file can be done from Print too */
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button, /* accessible from settings */
    /*#appMenu-extensions-themes-button, /* accessible from settings */
    /*#appMenu-bookmarks-button, /* submenu */
    /*#appMenu-history-button, /* submenu */
    /*#appMenu-more-button2, /* submenu */
    /*#appMenu-help-button2, /* submenu */
    .subviewbutton[shortcut]::after { /* menu shortcuts ("Ctrl+T" etc.) */
        display: none !important;
    }
}

browser.css

/* Copyright 2022 plata
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* Move navigation bar to bottom */
    #browser {
        -moz-box-ordinal-group: 0 !important; /* before FF 113 */
        order: -1 !important; /* since FF 113 */
    }

    /* Hide navigation bar in kiosk mode (to prevent bug #29). We can assume FF
     * is in kiosk mode when fullscreen and max-width conditions are met,
     * because at this max-width the fullscreen button is hidden
     * (see appMenu.css). */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen] {
        display: none;
    }

    /* Hide minimize/maximize/close buttons */
    .titlebar-buttonbox-container {
        display: none;
    }

    /* https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/toolbars_below_content.css  */
    #TabsToolbar > .titlebar-buttonbox-container {
      display: none;
    }
    /* Fix panels sizing */
    .panel-viewstack {
      max-height: unset !important;
    }

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --widget-overflow-margin: 66px;
        --unified-extensions-panel-margin: 66px;
        --customizationui-widget-panel-margin: 66px;
        --appMenu-popup-margin: 66px;
        --BMB_bookmarksPopup-margin: 66px;
    }
    :root[uidensity="touch"] {
        --widget-overflow-margin: 72px;
        --unified-extensions-panel-margin: 72px;
        --customizationui-widget-panel-margin: 72px;
        --appMenu-popup-margin: 72px;
        --BMB_bookmarksPopup-margin: 72px;
    }

    /* Adjust Widget Overflow Menu (») spawn height */
    #widget-overflow {
        margin-bottom: var(--widget-overflow-margin) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Adjust Main App Menu (≡) spawn height */
    #appMenu-popup {
        margin-bottom: var(--appMenu-popup-margin) !important;
    }

    /* Adjust Bookmarks Menu (★) spawn height */
    #BMB_bookmarksPopup {
        margin-bottom: var(--BMB_bookmarksPopup-margin) !important;
    }

}

editBookmarkPanel.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* The only way I (ollieparanoid) found to make this not glitchy, was to
     * reduce the bookmark panel to the minimum amount of useful controls and
     * hardcode width and height. Patches to improve this welcome, but make
     * sure that you don't introduce new UI glitches by doing extensive
     * testing. */

    #editBookmarkPanel {
        /*margin-top: -390px !important;
        height: 200px;
        max-height: 200px;
        max-width: calc(100vw - 100px);*/
        background-color: var(--arrowpanel-background) !important;
        margin-bottom: 225px !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }

    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator {
        display: none !important;
    }

    #editBookmarkPanelContent {
        /*max-width: 250px !important;
        width: 250px !important;
        padding-right: 20px;*/
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }

    /* Hide the screenshot and the line below it. The page is right there when
     * you bring up the menu, no need for a screenshot. Also it has a glitch
     * when taking the screenshot in mobile portrait view, half the screenshot
     * is just black. Let's rather use the space to edit the bookmark
     * information. */
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator {
        display: none;
    }

    #editBMPanel_folderRow,
    .editBMPanel_folderRow,
    #editBMPanel_tagsRow,
    .editBMPanel_tagsRow {
        display: none;
    }

    #editBookmarkPanelBottomButtons {
        /*width: 250px !important;
        min-width: 250px !important;
        padding: 0px !important;
        justify-content: flex-start !important;
        margin: 0px 0px 20px 0px !important;*/
        margin-top: -5px !important;
        margin-left: -50px !important;
    }
}

findbar.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    .findbar-container {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        /*height: 150px !important;*/
        height: 40px !important;
    }

    .findbar-textbox {
        /* Overwrite fixed size, so the X on the right shows up */
        width: 100% !important;
    }

    .findbar-container checkbox {
        /* Add space around the buttons, looks nicer and makes it easier to hit
         * them with the finger. */
        padding: 10px 0px;
    }

    /* Save space */
    .findbar-highlight,
    .findbar-case-sensitive,
    .findbar-match-diacritics,
    .findbar-entire-word,
    /*.found-matches,*/
    .findbar-find-status,
    .find-status-icon {
        display: none;
    }

}

popups.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* Now that the navbar is at the bottom, we need to set an offset to have
     * the notifications (like the one for installing addons) displayed
     * on-screen. */
    #notification-popup {
        /*margin-left: -200px !important;*/
        margin-top: -500px !important;
        margin-right: -500px !important;
        height: calc(100vh - 250px) !important;
        max-width: 100vw !important;
    }

    #downloadsPanel-mainView {
        max-width: calc(100vw - 10px);
    }

    /* Menu that appears when long-pressing the back-button */
    #backForwardMenu {
        margin-top: -250px;
        height: 200px;
        min-height: 200px;
        max-width: 100vw !important;
    }

    /* Hide some context menu items */
    #context-inspect,
    #context-inspect-a11y,
    #context-savelinktopocket,
    #context-searchselect,
    #context-sendlinktodevice,
    #context-viewpartialsource-selection,
    #inspect-separator {
        display: none !important
    }

    /* fix flickering of the protections, permissions,
     * widget overflow and identity popups */
    #protections-popup,
    #permission-popup,
    #widget-overflow,
    #identity-popup {
        max-width: 100vw !important;
    }

    /* fix the protections popup gettting
     * too wide, making controls unaccessible */
    #protections-popup-mainView {
        min-width: 100vw !important;
        max-width: 100vw !important;
    }

    /* fix flicker on extension menus.
     * The compromise is that the overflow menu always use
     * all available height.
     * The -80px is here to prevent covering the main bars */
    #widget-overflow,
    #widget-overflow-mainView {
        height: calc(100vh - 80px) !important;
    }

    /* Adjust Tab Manager Menu to fix flickering */
    #customizationui-widget-panel {
        width: 100vw !important;
    }

    /* Adjust Bookmarks Menu (★) and fix flickering */
    #BMB_bookmarksPopup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

}

root.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Reduce minimum window width */
:root {
    min-width: 300px !important;
}

tabmenu.css

/* Copyright 2022 Peter Mack, Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* Even when not in private browsing mode, reserve space to the right of
     * the tab bar for the private-browsing-indicator (that mask icon). This
     * gives the tab bar a consistent width in both the regular and the private
     * browsing mode, so the increased width hack below looks good in both. */
    /*#titlebar {
        padding-right: 30px;
    }
    hbox.private-browsing-indicator {
        position: fixed !important;
        right: 0px;
        bottom: 50px;
        display: block;
    }*/

    /* Increase tab width, to have more space for displaying the title of the
     * website and to make the "all tabs" button show up. */
    /*#tabbrowser-tabs {
        --tab-min-width: calc(100vw - 116px) !important;
    }*/

    /* Rotate the arrow on the "all tabs" button to point upwards, since the
     * tabs and searchbar were moved to the bottom. */
    /*#alltabs-button {
        transform: rotate(180deg) !important;
    }*/

    /* All tabs menu: hide scroll buttons */
    /*#scrollbutton-up,
    #scrollbutton-down {
        display: none !important;
    }*/

    /* All tabs menu: hide the search and the separator below it. */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Similar hack to what's in appMenu.css to properly spawn the "all tabs"
     * popup above the navigation menu */
    #customizationui-widget-panel {
        /* Further up than appmenu, because the "all tabs" button that spawns
         * this menu is above the hamburger button that spawns the regular
         * menu. */
        /*margin-top: -360px !important;*/
        padding-left: 10px !important;
        padding-right: 10px !important;
        /*height: 320px;*/
        /*max-height: 320px;*/
    }

    /*#allTabsMenu-allTabsView vbox.panel-subview-body {
        /* Use the whole height */
        /*height: 300px !important;
        /*max-height: 300px !important;
        /* When messing around with tabs, it gets into a state where it does
         * not use the whole height anymore, it becomes a tiny window. Removing
         * this attribute fixes it. Since FF 113, this no longer has any
         * effect, but it doesn't seem to be necessary either. */
        /*-moz-box-flex: initial !important;
    }*/

    /*#allTabsMenu-allTabsView vbox.panel-subview-body:first-child {
        /* the allTabsMenu has a vbox.panel-subview-body inside another one.
         * With -moz-box-flex: initial, it will show a scroll bar in each, but
         * we only want one scrollbar. */
        /*overflow-y: hidden !important;
    }*/

    #allTabsMenu-multiView box.panel-viewstack { /* before FF 102 or earlier */
        /* Use the whole height */
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack { /* since FF 113 */
        /* Use the whole height */
        /*height: 300px !important;
        max-height: 300px !important;*/
        height: 330px !important;
        max-height: 330px !important;
    }

    #allTabsMenu-allTabsViewTabs, /* before FF 106 */
    #allTabsMenu-allTabsView-tabs { /* since FF 106 */
        /* Make sure tabs with long titles don't exceed the all tabs menu */
        /*max-width: calc(100vw - 20px);*/
        max-width: calc(100vw - 30px);
        /* Fix padding */
        padding-top: 2px !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

}

urlbar.css

/* Copyright 2022 Oliver Smith
 * SPDX-License-Identifier: MPL-2.0 */

/* Reduce minimum window width */
#urlbar-container {
    min-width: 150px !important;
    flex-shrink: 1 !important;
}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

/*@media (max-width: 700px) {*/
    /* Remove various buttons left and right of the URL bar:
       - forward-button: also reachable via longpress of back button
       - home-button: not important enough
       - customizableui-special-spring: empty space
       - library-button: also reachable via PanelUI-menu-button
       - sidebar-button: not useful on mobile (we try to gain horizontal space)
       - fxa-toolbar-menu-button: firefox cloud stuff, also reachable via
         #PanelUI-menu-button
    */
    /* #back-button */
    #forward-button,
    /* #reload-button */
    /*#home-button,*/
    #customizableui-special-spring1,
    /* (urlbar) */
    #customizableui-special-spring2,
    #library-button,
    #sidebar-button,
    #fxa-toolbar-menu-button
    /* #PanelUI-menu-button */ {
        display: none !important;
    }

    #urlbar {
        padding: 0px 5px;
    }

    /* Smaller font: show more of the URL */
    #urlbar-input {
        font-size: 9pt !important;
    }

    /* Focused urlbar: hide all icons around it, so we have more space to edit the URL */
    #urlbar[focused] #remote-control-box,
    #urlbar[focused] #identity-box,
    #urlbar[focused] #tracking-protection-icon-container,
    /* #urlbar-input */
    #urlbar[focused] #reader-mode-button,
    #urlbar[focused] #page-action-buttons {
        display: none;
    }

    /* Label of "identity icons", e.g. firefox specific pages look weird
     * when ellipsed, e.g. "F..x" instead of "Firefox". So just hide this
     * label. The icon itself is still visible. */
    #identity-icon-label {
        display: none;
    }

    /* Move urlbar results to cover the whole displayed website, instead of
     * being below the urlbar. */
    .urlbarView {
        position: fixed !important;
        inset: 0px 0px 84px 0px;
        width: 100% !important;

        background: var(--arrowpanel-background);

        margin: 0px !important;
        margin-inline: 0px !important;
        border-inline: 0px !important;

        overflow-y:  auto !important;
        overflow-x: none !important;
        scrollbar-width: none;
    }

    /* Bookmarks toolbar. Firefox shows it for some reason when opening a
     * private browsing window, even if it is not enabled in the normal
     * window view. Hide it for mobile, it eats precious space and can't be
     * organized properly on mobile anyway. Using the searchbar to filter
     * through bookmarks is much more efficient. */
    #PersonalToolbar {
        display: none;
    }

    /* If the bookmarks toolbar is configured to only show on the new tab page,
     * Firefox makes the toolbar overlap the browser. When it's then hidden by
     * the rule above, the urlbar is pushed off the bottom of the window. To
     * prevent this, set the height of the overlapped toolbar to 0. */
    :root {
        --bookmarks-toolbar-overlapping-browser-height: 0 !important;
    }
}

/* Even though amazon is removed as search engine in policies.json, it gets
 * installed when FF starts for the first time. Hide the button in "This time,
 * search with" inside the urlbar. Match localizations like Amazon.de with this
 * regex. */
button[id^='urlbar-engine-one-off-item-Amazon'] {
    display: none !important;
}

my (user0) alternative to the browser.css file to place the Tab Bar at the top of the screen and the Nav Bar at the bottom of the screen:

alt-browser-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --alltabs-button-position: 3.5px !important;
        --widget-overflow-margin: 22px;
        --unified-extensions-panel-margin: 22px;
        --customizationui-widget-panel-margin: 22px;
        --appMenu-popup-margin: 22px;
        --BMB_bookmarksPopup-margin: 22px;
    }
    :root[uidensity="touch"] {
        --alltabs-button-position: 4.5px !important;
        --widget-overflow-margin: 23px;
        --unified-extensions-panel-margin: 23px;
        --customizationui-widget-panel-margin: 23px;
        --appMenu-popup-margin: 23px;
        --BMB_bookmarksPopup-margin: 23px;
    }
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Move Nav Bar to bottom */
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Adjust Widget Overflow Menu (») spawn height */
    #widget-overflow {
        margin-bottom: var(--widget-overflow-margin) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Adjust Main App Menu (≡) spawn height */
    #appMenu-popup {
        margin-bottom: var(--appMenu-popup-margin) !important;
    }

    /* Adjust Bookmarks Menu (★) spawn height */
    #BMB_bookmarksPopup {
        margin-bottom: var(--BMB_bookmarksPopup-margin) !important;
    }

}

some code by MrOtherGuy:

hide_tabs_scrollbuttons.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/hide_tabs_scrollbuttons.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* This should hide tabs scrollbuttons in a manner that preserves the ability to move tab strip when reordering tabs */

#tabbrowser-arrowscrollbox {
    --uc-compat-scrollbutton-margin: 1px; /* compatibility for non_floating_sharp_tabs.css */
    --uc-scrollbutton-up-background: linear-gradient(-90deg,transparent,var(--lwt-accent-color) 35%);
    --uc-scrollbutton-down-background: linear-gradient(90deg,transparent,var(--lwt-accent-color) 35%);
}

#tabbrowser-tabs:not([movingtab]) {
    --uc-scroll-visibility: hidden;
}
#tabbrowser-tabs[overflow] {
    --uc-scrollbox-base-margin: -31px;
    --uc-scrollbox-margin: calc(var(--uc-scrollbox-base-margin) + var(--tab-shadow-max-size));
}
:root[uidensity="compact"] #tabbrowser-tabs[overflow] {
    --uc-scrollbox-base-margin: -25px;
}
#tabbrowser-arrowscrollbox:not([scrolledtostart="true"]) {
    --uc-scrollbox-overflow-start-margin: -1px;
}
#scrollbutton-up ~ spacer {
    visibility: visible !important;
}
spacer[part="overflow-start-indicator"] {
    -moz-box-ordinal-group: 0; /* Fx < 112 compatibility */
    order: -1;
    margin-inline-start: var(--uc-scrollbox-overflow-start-margin,-0.5px) !important;
}
spacer[part="overflow-end-indicator"] {
    -moz-box-ordinal-group: 2; /* Fx < 112 compatibility */
    order: 2;
}

#scrollbutton-down[disabled="true"] > .toolbarbutton-icon,
#scrollbutton-up[disabled="true"] > .toolbarbutton-icon {
    opacity: 0.4;
} 
#scrollbutton-up,
#scrollbutton-down {
    position: relative;
    z-index: 1;
    visibility: var(--uc-scroll-visibility,visible);
    background-clip: border-box !important;
    background-origin: initial !important;
    background-repeat: no-repeat !important;
    opacity: 1 !important;
}
#scrollbutton-up {
    margin-inline-start: calc(0px - var(--tab-shadow-max-size,0px)) !important;
    background-image: var(--uc-scrollbutton-up-background);
}
#scrollbutton-down {
    margin-inline-end: calc(0px - var(--tab-shadow-max-size,0px)) !important;
    background-image: var(--uc-scrollbutton-down-background);
}
.scrollbox-clip {
    margin-inline: var(--uc-scrollbox-margin,0px);
}

/* Need to reset some things for other scrollboxes */
.menupopup-arrowscrollbox {
    --tab-shadow-max-size: 0;
}

tab_close_button_always_on_hover.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/tab_close_button_always_on_hover.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Always show tab close button on hover and never otherwise */
.tabbrowser-tab .tab-close-button {
    display: none;
}
.tabbrowser-tab:not([pinned]):hover .tab-close-button {
    display: flex !important;
    align-items: center;
}

tabs_fill_available_width.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/tabs_fill_available_width.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Why 100vw? Tab closing requires width animation to end and "none" can't be animated */
    .tabbrowser-tab[fadein]:not([style^="max-width"]) {
        max-width: 100vw !important;
    }

}

some code by MrOtherGuy (modified by user0):

iconized_main_menu.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/iconized_main_menu.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Adds icons to main menu items which were removed in Proton */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image{
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 8px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before{
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2{ list-style-image: url("chrome://browser/skin/new-tab.svg") }
#appMenu-new-window-button2{ list-style-image: url("chrome://browser/skin/window.svg") }
#appMenu-new-private-window-button2{ list-style-image: url("chrome://browser/skin/privateBrowsing.svg") }
#appMenu-bookmarks-button{ list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg") }
#appMenu-history-button{ list-style-image: url("chrome://browser/skin/history.svg") }
#appMenu-downloads-button{ list-style-image: url("chrome://browser/skin/downloads/downloads.svg") }
#appMenu-passwords-button{ list-style-image: url("chrome://browser/skin/login.svg") }
#appMenu-extensions-themes-button{ list-style-image: url("chrome://mozapps/skin/extensions/extension.svg") }
#appMenu-print-button2{ list-style-image: url("chrome://global/skin/icons/print.svg") }
#appMenu-save-file-button2{ list-style-image: url("chrome://browser/skin/save.svg") }
#appMenu-find-button2{ list-style-image: url("chrome://global/skin/icons/search-glass.svg") }
#appMenu-settings-button{ list-style-image: url("chrome://global/skin/icons/settings.svg") }
#appMenu-more-button2{ list-style-image: url("chrome://global/skin/icons/developer.svg") }
#appMenu-help-button2{ list-style-image: url("chrome://global/skin/icons/info.svg") }
#appMenu-quit-button2{ list-style-image: url("chrome://devtools/skin/images/search-clear.svg") }
#appMenu-translate-button{ list-style-image: url("chrome://browser/skin/translations.svg") }
#appMenu-zoom-controls::before{ background-image: url("chrome://browser/skin/fullscreen.svg") }
/* Use account-button icon for signed in sync item */
/*#appMenu-fxa-status2[fxastatus] > toolbarbutton::before{ background-image: var(--avatar-image-url) }*/
/* Add somewhat hacky separator to zoom controls so it looks consistent */
/*#appMenu-protonMainView > .panel-subview-body::after{
  content: "";
  display: flex;
  border-bottom: 1px solid var(--panel-separator-color);
  margin: var(--panel-separator-margin);
}
#appMenu-find-button2 ~ *{
  order: 2;
}*/

round_ui_items.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/round_ui_items.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Make bunch of things in the main UI round */

:root {
    --toolbarbutton-border-radius: 12px !important;
    --tab-border-radius: 14px !important;
}
#urlbar-input-container > box:hover,
#urlbar-input-container > box[open],
#main-menubar >    menu,
.titlebar-button:hover,
#scrollbutton-up,
#scrollbutton-down,
.tab-close-button,
.close-icon > image,
#page-action-buttons > :hover,
.panel-arrowcontent,
.urlbarView-row-inner,
.search-one-offs button,
.subviewbutton-back,
.toolbaritem-combined-buttons > toolbarbutton,
#PopupSearchAutoComplete,
menupopup {
    border-radius: 10px;
}

button,
.tab-background {
    border-radius: 14px !important;
}

.panel-arrowcontent {
    margin-inline-end: 0 !important;
}
.panel-arrow {
    margin-inline: 17px !important;
}

menupopup {
    -moz-appearance: none !important;
    overflow: -moz-hidden-unscrollable !important;
}

.tabbrowser-tab[selected]::after,
.tabbrowser-tab[beforeselected-visible]::after {
    border-color: transparent !important;
}

/*#nav-bar {
    box-shadow: none !important;
    margin-top: 3px;
}*/
.tab-line {
    display: none;
}

.tab-background[selected] {
    border-top-width: 3px !important;
    border-bottom-width: 3px !important;
    border-left-width: 3px !important;
    border-right-width: 3px !important;
    border-radius: 14px !important;
}
.tabbrowser-tab[selected] {
    z-index: auto !important;
}

/*.urlbar-icon,
toolbar toolbarbutton:not(#back-button):not(.bookmark-item):not(.titlebar-button) > .toolbarbutton-icon {
    border-radius: 12px !important;
}*/

menugroup:hover > menuitem {
    border-radius: 16px !important;
}

/* URL Bar and Search Bar shape */
#urlbar,
#searchbar,
#urlbar-input,
#urlbar-input-container {
    border-radius: 12px !important;
}
#urlbar-background {
    border: none !important;
    border-radius: 12px !important;
}

/* Find Bar shape */
input.findbar-textbox {
    border-radius: 9px !important;
    font-size: 14px !important;
}

numbered_tabs.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/numbered_tabs.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --tab-number-position: calc(var(--toolbarbutton-inner-padding) * 1.6 );
    }
    :root[uidensity="touch"] {
        --tab-number-position: calc(var(--toolbarbutton-inner-padding) * 1.8 );
    }

    /* Show the tab number after tab content, right-align it, and fix its position directly on the tab close button */
    #tabbrowser-tabs {
        counter-reset: nth-tab 0; /* Change to -1 for 0-indexing */
    }
    .tabbrowser-tab .tab-content::after {
        content: counter(nth-tab) " ";
        counter-increment: nth-tab;
        position: absolute !important;
        position: fixed;
        right: 24px;
        bottom: var(--tab-number-position);
        width: 0 !important;
    }

    /* Hide tab close button on unpinned tabs, and reserve space for tab number */
    .tabbrowser-tab:not(:hover,[pinned]) .tab-close-button {
        display: initial !important;
        visibility: hidden !important;
    }

    /* Hide tab number on pinned tabs and when hovering on unpinned tabs so that tab close button is clickable */
    .tabbrowser-tab[pinned] .tab-content::after,
    .tabbrowser-tab:not([pinned]):hover .tab-content::after {
        visibility: hidden !important;
    }

    /* Adjust tab close button opacity, border, and shape */
    .tab-close-button {
        position: absolute !important;
        margin-right: -8px !important;
        opacity: 0.5 !important;
        border: 2px solid white !important;
        height: 36px !important;
        width: 36px !important;
    }

}

tab_animated_active_border.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/tab_animated_active_border.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Creates a colorful animated border around active tab */

@keyframes filter {
    from {
        filter: hue-rotate(0deg)
    }
    to {
        filter: hue-rotate(360deg)
    }
}
 
.tabbrowser-tab[selected] > .tab-stack::before {
    grid-area: 1/1;
    content: "";
    display: inherit;
    margin-block: var(--tab-block-margin);
    border-radius: var(--tab-border-radius);
    z-index: 0;
    background-image: conic-gradient(
        hsl(0 100% 70%),
        hsl(60 100% 45%) 70deg,
        hsl(120 100% 55%) 105deg,
        hsl(160 100% 60%) 160deg,
        hsl(200 100% 60%) 200deg,
        hsl(240 100% 65%) 255deg,
        hsl(300 100% 60%) 290deg,
        hsl(360 100% 70%) 360deg);
    background-size: cover;
    background-position: center;
    animation: filter steps(30) 2s infinite;
}
.tab-background[selected] {
    border: 1px solid transparent !important;
    outline: none !important;
    background-clip: padding-box !important;
}

some code by reddit users /u/BatDogOnBatMobile, /u/moko1960, and /u/It_Was_The_Other_Guy (modified by user0):

tab_counter.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source from reddit users /u/BatDogOnBatMobile, /u/moko1960, and /u/It_Was_The_Other_Guy
     https://teddit.net/r/FirefoxCSS/comments/s4wsww/
     https://teddit.net/r/FirefoxCSS/comments/yb8tr9/ */

/* Show Tab Manager Menu button */
#alltabs-button {
    display: -moz-box !important;
}

/* Tab Manager Menu button tab counter */
#TabsToolbar-customization-target {
    counter-reset: tabCount;
}
.tabbrowser-tab {
    counter-increment: tabCount;
}
#alltabs-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
    visibility: collapse !important;
}
#alltabs-button > .toolbarbutton-badge-stack {
     position: relative !important;
}
#alltabs-button > .toolbarbutton-badge-stack::before {
    content: counter(tabCount);
    color: var(--toolbarbutton-icon-fill);
    opacity: var(--toolbarbutton-icon-fill-opacity);
    position: absolute;
    bottom: var(--toolbarbutton-inner-padding);
    left: 50%;
    transform: translateX(-50%);
}
#alltabs-button > .toolbarbutton-badge-stack {
    border-radius: var(--toolbarbutton-border-radius);
}

/* Tab Manager Menu tab counter */
#allTabsMenu-allTabsViewTabs, /* before FF 106 */
#allTabsMenu-allTabsView-tabs { /* since FF 106 */
    counter-reset: nn_tabs 0 !important;
}
.all-tabs-button::before {
    display: -moz-inline-box !important;
    -moz-padding-end: 8px !important;
    content: counter(nn_tabs) !important;
    font-size: 12px !important; 
    margin-top: -2px !important; 
    margin-right: -2px !important;
}
.all-tabs-item {
    counter-increment: nn_tabs !important;
}

some code by me (user0):

extensions_menu.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Remove header, separators, and manage-extensions button */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 325px !important;
        max-height: 325px !important;
        width: calc(100vw - 30px) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

}

custom_rules.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Disable tab loading burst
   (because it's annoying) */
.tab-loading-burst {
    display: none !important;
}

/* Tabs Toolbar and Container tab line color
   (hides container tab line above tab by making it the same color as the Tabs Toolbar) */
#TabsToolbar,
.tabbrowser-tab[usercontextid] > .tab-stack > .tab-background > .tab-context-line {
    background-color: var(--tab-bgcolor) !important;
}

/* Menubar color
   (hides the line at the top of the screen when Menubar is hidden) */
toolbar[type=menubar] {
    background-color: black !important;
    color: var(--toolbar-color) !important;
}

/* Navbar bottom border color */
#navigator-toolbox {
    border-bottom-color: black !important;
}

/* Resist Fingerprinting Letterbox background color */
:root {
    --tabpanel-background-color: black !important;
}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Remove Fullscreen popup */
    .pointerlockfswarning {
        display: none !important;
    }

    /* Remove tab overflow indicators */
    spacer[part=overflow-start-indicator],
    spacer[part=overflow-end-indicator] {
        display: none !important;
    }

    /* Remove spacers on left and right of main tab view */
    #tabbrowser-tabs[haspinnedtabs]:not([positionpinnedtabs]) > #tabbrowser-arrowscrollbox > .tabbrowser-tab[first-visible-unpinned-tab] {
        margin-inline-start: 0px !important;
    }
    .titlebar-spacer[type="post-tabs"] {
        display: none !important;
    }

    /* Remove items from URL Bar */
    #tracking-protection-icon-container,
    #identity-permission-box,
    #userContext-indicator,
    /*#page-action-buttons,*/
    #pageActionButton {
        display: none !important;
    }

    /* URL Bar font resizing */
    #urlbar-input {
        font-size: 10pt !important;
    }
    #urlbar[focused] #urlbar-input {
        font-size: calc(var(--urlbar-height) - 9px) !important;
    }

    /* Hide inactive tab close button (x)
         to prevent accidentally closing tabs when selecting them */
    .tab-close-button:not([selected]),
    .tabbrowser-tab:not([selected]):hover .tab-close-button {
        visibility: hidden !important;
    }

}

single_tab_mode-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 48px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 166px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 54px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 171.5px);
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide Title Bar, Newtab button, and New-tab button */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container,
    #new-tab-button,
    #tabs-newtab-button {
        display: none !important;
    }

    /* Hide unpinned inactive tabs */
    .tabbrowser-tab:not([pinned]):not([selected]) {
        visibility: collapse !important;
        min-width: 0 !important;
    }

    /* Expand unpinned active tab */
    #tabbrowser-tabs:not([haspinnedtabs]) > #tabbrowser-arrowscrollbox > .tabbrowser-tab[selected] {
        min-width: 100% !important;
    }
    #tabbrowser-tabs[haspinnedtabs] > #tabbrowser-arrowscrollbox > .tabbrowser-tab:not([pinned])[selected] {
        min-width: 83.5% !important;
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

}

alt-single_tab_mode-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 166px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 171.5px);
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide Title Bar, Newtab button, and New-tab button */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container,
    #new-tab-button,
    #tabs-newtab-button {
        display: none !important;
    }

    /* Hide unpinned inactive tabs */
    .tabbrowser-tab:not([pinned]):not([selected]) {
        visibility: collapse !important;
        min-width: 0 !important;
    }

    /* Expand unpinned active tab */
    #tabbrowser-tabs:not([haspinnedtabs]) > #tabbrowser-arrowscrollbox > .tabbrowser-tab[selected] {
        min-width: 100% !important;
    }
    #tabbrowser-tabs[haspinnedtabs] > #tabbrowser-arrowscrollbox > .tabbrowser-tab:not([pinned])[selected] {
        min-width: 83.5% !important;
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

}

single_tab_mode.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4.5px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 166px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5.5px;
        --alltabs-number-position: calc(var(--toolbarbutton-inner-padding) * 1.5 );
        --urlbar-width: calc(100vw - 171.5px);
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide Title Bar, Newtab button, and New-tab button */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container,
    #new-tab-button,
    #tabs-newtab-button {
        display: none !important;
    }

    /* Hide unpinned inactive tabs */
    .tabbrowser-tab:not([pinned]):not([selected]) {
        visibility: collapse !important;
        min-width: 0 !important;
    }

    /* Expand unpinned active tab */
    #tabbrowser-tabs:not([haspinnedtabs]) > #tabbrowser-arrowscrollbox > .tabbrowser-tab[selected] {
        min-width: 100% !important;
    }
    #tabbrowser-tabs[haspinnedtabs] > #tabbrowser-arrowscrollbox > .tabbrowser-tab:not([pinned])[selected] {
        min-width: 83.5% !important;
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

}

hide_tab_manager_menu_button.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Remove Tab Manager Menu button */
    #alltabs-button {
        display: none !important;
    }

}

hide_newtab_+_new-tab_buttons.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Hide Newtab and New-tab buttons */
    #new-tab-button,
    #tabs-newtab-button {
        display: none !important;
    }

}

new-tab-button.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Hide non-overflow Newtab button */
    #tabs-newtab-button {
        display: none !important;
    }

    /* Display overflow New-tab button by default and fix alignment */
    #new-tab-button { 
        display: initial !important;
        margin-top: 4px !important;
    }

}

tabs_larger_min-width.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Tab min-width resizing */
#tabbrowser-tabs {
    --tab-min-width: 24vw !important;
}

glow.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Inactive tab glow on hover */
.tabbrowser-tab:hover > .tab-stack > .tab-background:not([selected]) {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}

/* Newtab buttons (+) and Tab Manager button (v) glow on hover */
#alltabs-button:hover > .toolbarbutton-badge-stack,
#new-tab-button:hover,
#tabs-newtab-button:hover {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}

/* Back button glow on hover */
#back-button:not([disabled]):hover > .toolbarbutton-icon {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}

/* Forward button glow on hover */
#forward-button:not([disabled]):hover > .toolbarbutton-icon {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}

/* Urlbar glow */
#urlbar {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}
/* Urlbar glow on focus */
#urlbar[focused] {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
    box-shadow: 0 0 3px var(--uc-icon-glow-secondary) !important;
}
/* Urlbar glow on hover */
#urlbar:hover {
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
    box-shadow: 0 0 3px var(--uc-icon-glow-secondary) !important;
}

/* Navbar buttons glow */
#nav-bar toolbarbutton:hover:not(#back-button):not(#forward-button) { 
    filter: drop-shadow(0 0 2px var(--uc-icon-glow-secondary)) drop-shadow(0 0 1px var(--uc-icon-glow-primary));
}

colorful_inactive_tabs.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Inactive tab color */
.tabbrowser-tab:not(:hover,[pinned], [selected]) > .tab-stack > .tab-background {
    background-color: var(--lwt-selected-tab-background-color) !important;
}

/* Inactive tab color on hover */
.tabbrowser-tab:hover > .tab-stack > .tab-background:not([selected]) {
    background-color: var(--lwt-accent-color-inactive) !important;
}

/* Inactive pinned tab icon color */
.tab-icon-image[pinned]:not([selected]) {
    color: var(--lwt-accent-color) !important;
}

/* Inactive tab text and close button (x) color */
.tab-text:not([pinned]):not([selected]),
.tab-icon-image:not([pinned]):not([selected]),
.tab-close-button:not([pinned]):not([selected]) {
    color: var(--lwt-text-color) !important;
}

/* Inactive tab text and close button (x) color on hover */
.tabbrowser-tab:not([selected]):hover .tab-text,
.tabbrowser-tab:not([selected]):hover .tab-icon-image,
.tabbrowser-tab:not([selected]):hover .tab-close-button {
    color: var(--lwt-accent-color) !important;
}

borderless_transparent_active_tab.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Tab color */
.tab-background {
    background-color: transparent !important;
}

/* Tab border */
.tab-background[selected] {
    border: 0 transparent !important;
}

Note:

• single_tab_mode-alt.css = Tab Bar & Nav Bar at top of screen

• alt-single_tab_mode-alt.css = Tab Bar at top of screen + Nav Bar at bottom of screen

• single_tab_mode.css = Tab Bar & Nav Bar at bottom of screen

[Emma]

True Mobile Modes & Dynamic Popups:

true_mobile_landscape-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 205.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 209.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }
    
    /* Remove extra space above zoom controls in Main App Menu (≡) */
    #appMenu-zoom-controls {
        margin-top: 0 !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

}

true_mobile_landscape.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 205.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 209.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }
    
    /* Remove extra space above zoom controls in Main App Menu (≡) */
    #appMenu-zoom-controls {
        margin-top: 0 !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Move Nav Bar to bottom */
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

}

true_mobile_mode-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 166px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 171.5px);
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

}

true_mobile_mode.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 166px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 171.5px);
    }

    /* Move Main App Menu (≡) button to allow room for Tab Manager Menu button */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 41.5px;
        z-index: 2 !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack::before {
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.7 ) !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* Reduce URL Bar width */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }

}

dynamic_popups.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --unified-extensions-panel-padding: 112px;
        --customizationui-widget-panel-padding: 112px;
    }
    :root[uidensity="touch"] {
        --unified-extensions-panel-padding: 110px;
        --customizationui-widget-panel-padding: 110px;
    }

    /* Dynamically expand popups */
    #unified-extensions-view {
        height: calc(100vh - 171px) !important;
        max-height: calc(100vh - 171px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 165px) !important;
        max-height: calc(100vh - 165px) !important;
    }
    #appMenu-popup,
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 0 !important;
        height: calc(100vh - 107px) !important;
        max-height: calc(100vh - 107px) !important;
    }

    /* Adjust Unified Extensions Menu and Tab Manager Menu to fill screen width */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        padding: 0 !important;
    }
    #customizationui-widget-multiview {
        width: 100vw !important;
    }
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 10px) !important;
    }
    #unified-extensions-view,
    #allTabsMenu-containerTabsButton,
    .all-tabs-item {
        width: calc(100vw - 10px) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: 6px !important;
        padding-top: var(--unified-extensions-panel-padding) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: 6px !important;
        padding-top: var(--customizationui-widget-panel-padding) !important;
    }

    /* Blend panels into background */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        background-color: black !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 350px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 300px !important;
    }

}

dynamic_popups_plus.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --unified-extensions-panel-padding: 25px;
        --customizationui-widget-panel-padding: 25px;
    }
    :root[uidensity="touch"] {
        --unified-extensions-panel-padding: 22px;
        --customizationui-widget-panel-padding: 22px;
    }

    /* Dynamically expand popups */
    #unified-extensions-view {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 95px) !important;
        max-height: calc(100vh - 95px) !important;
    }
    #appMenu-popup,
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 0 !important;
        height: calc(100vh - 107px) !important;
        max-height: calc(100vh - 107px) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: 6px !important;
        padding-top: var(--unified-extensions-panel-padding) !important;
        padding-bottom: 17px !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: 6px !important;
        padding-top: var(--customizationui-widget-panel-padding) !important;
        padding-bottom: 17px !important;
    }

    /* Blend panels into background */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        background-color: black !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 350px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 300px !important;
    }

}

dynamic_popups_max.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --unified-extensions-view-height: calc(100vh - 57px);
        --customizationui-widget-height: calc(100vh - 51px);
        --unified-extensions-panel-margin: 5px;
        --customizationui-widget-panel-margin: 5px;
    }
    :root[uidensity="touch"] {
        --unified-extensions-view-height: calc(100vh - 61px);
        --customizationui-widget-height: calc(100vh - 55px);
        --unified-extensions-panel-margin: 6px;
        --customizationui-widget-panel-margin: 6px;
    }

    /* Dynamically expand popups */
    #unified-extensions-view {
        height: var(--unified-extensions-view-height) !important;
        max-height: var(--unified-extensions-view-height) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: var(--customizationui-widget-height) !important;
        max-height: var(--customizationui-widget-height) !important;
    }
    #appMenu-popup,
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 0 !important;
        height: calc(100vh - 107px) !important;
        max-height: calc(100vh - 107px) !important;
    }

    /* Adjust Unified Extensions Menu and Tab Manager Menu to fill screen width */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        padding: 0 !important;
    }
    #customizationui-widget-multiview {
        width: 100vw !important;
    }
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 10px) !important;
    }
    #unified-extensions-view,
    #allTabsMenu-containerTabsButton,
    .all-tabs-item {
        width: calc(100vw - 10px) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Blend panels into background */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        background-color: black !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 370px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 300px !important;
    }

}

dynamic_popups_pro.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Dynamically expand popups */
    #unified-extensions-view {
        height: calc(100vh - 171px) !important;
        max-height: calc(100vh - 171px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 165px) !important;
        max-height: calc(100vh - 165px) !important;
    }
    #appMenu-popup,
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 0 !important;
        height: calc(100vh - 107px) !important;
        max-height: calc(100vh - 107px) !important;
    }

    /* Adjust Unified Extensions Menu and Tab Manager Menu to fill screen width */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        padding: 0 !important;
    }
    #customizationui-widget-multiview {
        width: 100vw !important;
    }
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 10px) !important;
    }
    #unified-extensions-view,
    #allTabsMenu-containerTabsButton,
    .all-tabs-item {
        width: calc(100vw - 10px) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: 6px !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: 6px !important;
    }

    /* Blend panels with views */
    panel {
        /* Default color: */
        /*--panel-background: var(--arrowpanel-background) !important;*/
        /* Fenix color: */
        --panel-background: var(--toolbar-bgcolor) !important;
        --panel-shadow: none !important;
    }
    #unified-extensions-panel {
        background-color: var(--arrowpanel-background) !important;
    }
    #customizationui-widget-panel {
        /* Default color: */
        /*background-color: var(--arrowpanel-background) !important;*/
        /* Fenix color: */
        background-color: var(--toolbar-bgcolor) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 350px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 300px !important;
    }

}

dynamic_popups_pro_max.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --unified-extensions-view-height: calc(100vh - 57px);
        --customizationui-widget-height: calc(100vh - 51px);
        --unified-extensions-panel-margin: 5px;
        --customizationui-widget-panel-margin: 5px;
    }
    :root[uidensity="touch"] {
        --unified-extensions-view-height: calc(100vh - 61px);
        --customizationui-widget-height: calc(100vh - 55px);
        --unified-extensions-panel-margin: 6px;
        --customizationui-widget-panel-margin: 6px;
    }

    /* Dynamically expand popups */
    #unified-extensions-view {
        height: var(--unified-extensions-view-height) !important;
        max-height: var(--unified-extensions-view-height) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: var(--customizationui-widget-height) !important;
        max-height: var(--customizationui-widget-height) !important;
    }
    #appMenu-popup,
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 0 !important;
        height: calc(100vh - 107px) !important;
        max-height: calc(100vh - 107px) !important;
    }

    /* Adjust Unified Extensions Menu and Tab Manager Menu to fill screen width */
    #unified-extensions-panel,
    #customizationui-widget-panel {
        padding: 0 !important;
    }
    #customizationui-widget-multiview {
        width: 100vw !important;
    }
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 10px) !important;
    }
    #unified-extensions-view,
    #allTabsMenu-containerTabsButton,
    .all-tabs-item {
        width: calc(100vw - 10px) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Blend panels with views */
    panel {
        /* Default color: */
        /*--panel-background: var(--arrowpanel-background) !important;*/
        /* Fenix color: */
        --panel-background: var(--toolbar-bgcolor) !important;
        --panel-shadow: none !important;
    }
    #unified-extensions-panel {
        background-color: var(--arrowpanel-background) !important;
    }
    #customizationui-widget-panel {
        /* Default color: */
        /*background-color: var(--arrowpanel-background) !important;*/
        /* Fenix color: */
        background-color: var(--toolbar-bgcolor) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 370px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 300px !important;
    }

}

Note:

• true_mobile_landscape-alt.css = No Tab Bar + Nav Bar at top of screen

• true_mobile_landscape.css = No Tab Bar + Nav Bar at bottom of screen

• true_mobile_mode-alt.css = No Tab Bar + Nav Bar at top of screen

• true_mobile_mode.css = No Tab Bar + Nav Bar at bottom of screen

• dynamic_popups.css = black screen + max-width popup at bottom

• dynamic_popups_plus.css = black screen + tall floating popup

• dynamic_popups_max.css = black screen + maximized popup

• dynamic_popups_pro.css = max-width popup at bottom + no curves

• dynamic_popups_pro_max.css = maximized popup + no curves

[Emma]

Fenix:

fenix_colors.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/color_variable_template.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

:root {
    /* Popup panels */
    --arrowpanel-background: rgb(41,29,79) !important;
    --arrowpanel-border-color: transparent !important;
    --arrowpanel-color: white !important;
    --arrowpanel-dimmed: rgb(97,84,124) !important;
    --arrowpanel-dimmed-further: rgb(66,50,98) !important;
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
    --panel-item-hover-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-item-active-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-banner-item-background-color: rgb(117,66,228) !important;
    --panel-banner-item-hover-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-active-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-update-supported-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-info-icon-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-color: white !important;
    --panel-description-color: white !important;
    --panel-disabled-color: gray !important;
    --menuitem-disabled-hover-background-color: transparent !important;

    /* window and toolbar background */
    --lwt-accent-color: rgb(117,66,228) !important;
    --lwt-accent-color-inactive: rgba(117,66,228,0.3) !important;
    --toolbar-non-lwt-bgcolor: rgb(41,29,79) !important;
    --toolbar-non-lwt-textcolor: white !important;
    --toolbar-bgcolor: rgb(43,42,51) !important;
    --toolbar-color: rgb(171,113,255) !important;
    --tabpanel-background-color: black !important;

    /* tabs with system theme - text is not controlled by variable */
    --tab-selected-bgcolor: rgb(117,66,228) !important;

    /* tabs with any other theme */
    --lwt-text-color: white !important;
    --lwt-selected-tab-background-color: rgb(117,66,228) !important;

    /* toolbar area */
    --toolbarbutton-icon-fill: white !important;
    --toolbarbutton-icon-fill-attention: white !important;
    --toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-icon-fill-attention: white !important;
    --lwt-toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --toolbarseparator-color: black !important;

    /* urlbar */
    --toolbar-field-border-color: rgb(28,27,34) !important;
    --toolbar-field-focus-border-color: rgb(28,27,34) !important;
    --urlbar-popup-url-color: white !important;
    --urlbar-box-bgcolor: var(--button-bgcolor);
    --urlbar-box-focus-bgcolor: var(--button-bgcolor);
    --urlbar-box-hover-bgcolor: var(--button-hover-bgcolor);
    --urlbar-box-active-bgcolor: var(--button-active-bgcolor);
    --urlbar-box-text-color: inherit;
    --urlbar-box-hover-text-color: var(--urlbar-box-text-color);
    --lwt-brighttext-url-color: #00ddff;

    /* urlbar Firefox < 92 */
    --lwt-toolbar-field-background-color: rgb(28,27,34) !important;
    --lwt-toolbar-field-focus: white !important;
    --lwt-toolbar-field-color: white !important;
    --lwt-toolbar-field-focus-color: white !important;

    /* urlbar Firefox 92+ */
    --toolbar-field-background-color: rgb(28,27,34) !important;
    --toolbar-field-focus-background-color: rgb(28,27,34) !important;
    --toolbar-field-icon-fill-attention: rgb(117,66,228) !important;
    --toolbar-field-color: white !important;
    --toolbar-field-focus-color: white !important;

    /* sidebar - note the sidebar-box rule for the header-area */
    --lwt-sidebar-background-color: rgb(41,29,79) !important;
    --lwt-sidebar-text-color: white !important;

    /* findbar */
    --focus-outline-color: rgb(117,66,228) !important;
    --input-border-color: rgb(117,66,228) !important;

    /* buttons and checkboxes */
    --button-bgcolor: rgb(117,66,228) !important;
    --button-color: white !important;
    --button-hover-bgcolor: rgb(144,89,255) !important;
    --button-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-bgcolor: rgb(117,66,228) !important;
    --button-primary-hover-bgcolor: rgb(144,89,255) !important;
    --button-primary-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-color: white !important;
    --in-content-primary-button-background: rgb(117,66,228) !important;
    --in-content-primary-button-background-hover: rgb(144,89,255) !important;
    --in-content-primary-button-background-active: rgb(144,89,255) !important;
    --buttons-destructive-bgcolor: #e22850;
    --buttons-destructive-hover-bgcolor: #c50042;
    --buttons-destructive-active-bgcolor: #810220;
    --buttons-destructive-color: #fbfbfe;
    --checkbox-unchecked-bgcolor: rgb(41,29,79) !important;
    --checkbox-unchecked-hover-bgcolor: rgb(144,89,255) !important;
    --checkbox-unchecked-active-bgcolor: rgb(144,89,255) !important;
    --checkbox-checked-border-color: rgb(117,66,228) !important;
    --checkbox-checked-bgcolor: rgb(117,66,228) !important;
    --checkbox-checked-color: white !important;
    --checkbox-checked-hover-bgcolor: rgba(144,89,255) !important;
    --checkbox-checked-active-bgcolor: rgba(144,89,255) !important;
    --uc-checkbox-checked-bgcolor: rgb(117,66,228) !important;

    /* icon glow */
    --uc-icon-glow-primary: rgb(117,66,228);
    --uc-icon-glow-secondary: white;
    --uc-icon-glow-hover-primary: rgb(117,66,228);
    --uc-icon-glow-hover-secondary: white;
}

/* line between nav-bar and tabs toolbar,
        also fallback color for border around selected tab */
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(65,64,72) !important;
}

/* Line above tabs */
#tabbrowser-tabs {
    --lwt-tab-line-color: none !important;
}

/* the header-area of sidebar needs this to work */
#sidebar-box {
    --sidebar-background-color: rgb(41,29,79) !important;
}

/* Find Bar */
.findbar-find-previous,
.findbar-find-next,
input.findbar-textbox,
findbar {
    border: none !important;
    box-shadow: none !important;
    background-color: var(--arrowpanel-background) !important;
    color: var(--toolbar-field-color) !important;
}

/* Context Menus */
menupopup {
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
}
menuseparator {
    display: none !important;
}
menu:hover,
menuitem:hover {
    background-color: var(--panel-item-hover-bgcolor) !important;
    color: var(--panel-color) !important;
}

/* Menu popup shadow */
.menupopup-arrowscrollbox {
    box-shadow: 0 5px 5px -3px rgba(0,0,0,0.2),
                0 8px 10px 1px rgba(0,0,0,0.14),
                0 3px 14px 2px rgba(0,0,0,0.12) !important;
}

/* "Saved to Library!" popup notification */
#confirmation-hint {
    --panel-background: var(--lwt-accent-color) !important;
    --panel-border-color: var(--lwt-accent-color) !important;
    --panel-color: var(--lwt-text-color) !important;
}

/* "Confirm before closing multiple tabs" popup checkboxes and dialog buttons */
.checkbox-check {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}
.dialog-button-box > button:nth-child(6) {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}

/* Main App Menu (≡), Tab Manager Menu, and Unified Extensions Menu */
panel {
    --panel-background: black !important;
    --panel-shadow: none !important;
}
.panel-viewstack {
    background-color: var(--arrowpanel-background) !important;
    border-color: var(--arrowpanel-background) !important;
}

/* Tab Manager Menu */
#allTabsMenu-allTabsView-tabs,
#allTabsMenu-allTabsView,
#allTabsMenu-containerTabsView {
    background-color: var(--toolbar-bgcolor) !important;
}
#allTabsMenu-containerTabsButton,
#allTabsMenu-containerTabsView > .panel-header {
    color: var(--toolbar-color) !important;
}
#allTabsMenu-containerTabsButton:hover {
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-item[selected] {
    background-color: var(--arrowpanel-dimmed-further) !important;
}
.all-tabs-item:hover[selected] {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--arrowpanel-dimmed) !important;
}
.all-tabs-item:hover:not([selected]) {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-close-button:hover {
    background-color: var(--toolbarbutton-hover-background) !important;
}

/* Private Browsing Mode theme for URL Bar and Nav Bar */
:root {
    --toolbar-field-border-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-border-color: var(--arrowpanel-background) !important;
    --lwt-toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-background-color: var(--arrowpanel-background) !important;
}
#nav-bar {
    background-image: -moz-linear-gradient(to right, rgb(112,34,145), rgb(57,52,115)) !important;
}
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(134,93,180) !important;
}

fenix_theme.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar {
        width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        padding-top: 8px !important;
        width: 230px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Remove Back button */
    #back-button {
        display: none !important;
    }

    /* Hide Private Browsing Indicator */
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 9px !important;
        font-weight: 600 !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

fenix-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar {
        width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        padding-top: 8px !important;
        width: 230px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Remove Back button */
    #back-button {
        display: none !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 9px !important;
        font-weight: 600 !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

fenix.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar {
        width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        padding-top: 8px !important;
        width: 230px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Remove Back button */
    #back-button {
        display: none !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Find Bar */
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 9px !important;
        font-weight: 600 !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

}

Note:

• fenix_colors.css can be added to any userChrome to add colors to match Firefox for Android.

• fenix_theme.css is designed to be used with a mobile style, for those that want the Firefox for Android (fenix) theme and don’t want to hide the Tab Bar. It must be imported into the userChrome.css file below the single_tab import, as shown in the userChrome section of Styles & Screenshots (post 61).

• fenix-alt.css is a combination of the following files:

  • fenix_theme.css
  • true_mobile_mode-alt.css

• fenix.css is a combination of the following files:

  • fenix_theme.css
  • true_mobile_mode.css

[Emma]

Fenix Fox (alt) & Fenix Fox:

fenix_fox-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Resist Fingerprinting Letterbox background color and minimum width for display and URL Bar */
:root {
    --tabpanel-background-color: black !important;
    min-width: 300px !important;
}
#urlbar-container {
    min-width: 150px !important;
    flex-shrink: 1 !important;
}

/* Menu Bar color
   (hides the line at the top/bottom of the screen when Menubar is hidden) */
toolbar[type=menubar] {
    background-color: black !important;
    color: var(--toolbar-color) !important;
}

/* Nav Bar bottom border color */
#navigator-toolbox {
    border-bottom-color: black !important;
}

/* Remove popup warning when enterimg Fullscreen */
.pointerlockfswarning {
    display: none !important;
}

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Show Tab Manager Menu button */
#alltabs-button {
    display: -moz-box !important;
}

/* Tab Manager Menu button tab counter */
#TabsToolbar-customization-target {
    counter-reset: tabCount;
}
.tabbrowser-tab {
    counter-increment: tabCount;
}
#alltabs-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
    visibility: collapse !important;
}
#alltabs-button > .toolbarbutton-badge-stack {
     position: relative !important;
}
#alltabs-button > .toolbarbutton-badge-stack::before {
    content: counter(tabCount);
    color: var(--toolbarbutton-icon-fill);
    opacity: var(--toolbarbutton-icon-fill-opacity);
    position: absolute;
    bottom: var(--toolbarbutton-inner-padding);
    left: 50%;
    transform: translateX(-50%);
}
#alltabs-button > .toolbarbutton-badge-stack {
    border-radius: var(--toolbarbutton-border-radius);
}

/* Tab Manager Menu tab counter */
#allTabsMenu-allTabsViewTabs, /* before FF 106 */
#allTabsMenu-allTabsView-tabs { /* since FF 106 */
    counter-reset: nn_tabs 0 !important;
}
.all-tabs-button::before {
    display: -moz-inline-box !important;
    -moz-padding-end: 8px !important;
    content: counter(nn_tabs) !important;
    font-size: 12px !important; 
    margin-top: -2px !important; 
    margin-right: -2px !important;
}
.all-tabs-item {
    counter-increment: nn_tabs !important;
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar*/
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        height: 340px;
        max-height: 340px;
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 4px !important;
        height: 318px !important;
        max-height: 318px !important;
        width: 230px !important;
    }
    #appMenu-multiView box.panel-viewstack:first-child {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        margin-bottom: 225px !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar */
    .findbar-container {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        height: 40px !important;
    }
    .findbar-textbox {
        width: 100% !important;
    }
    .findbar-container checkbox {
        padding: 10px 0px;
    }
    .findbar-highlight,
    .findbar-case-sensitive,
    .findbar-match-diacritics,
    .findbar-entire-word,
    /*.found-matches,*/
    .findbar-find-status,
    .find-status-icon {
        display: none;
    }
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Fix Popups */
    #notification-popup {
        margin-top: -500px !important;
        margin-right: -500px !important;
        height: calc(100vh - 250px) !important;
        max-width: 100vw !important;
    }
    #downloadsPanel-mainView {
        max-width: calc(100vw - 10px);
    }
    #backForwardMenu {
        margin-top: -250px;
        height: 200px;
        min-height: 200px;
        max-width: 100vw !important;
    }
    #context-inspect,
    #context-inspect-a11y,
    #context-savelinktopocket,
    #context-searchselect,
    #context-sendlinktodevice,
    #context-viewpartialsource-selection,
    #inspect-separator {
        display: none !important
    }
    #protections-popup,
    #permission-popup,
    #widget-overflow,
    #identity-popup {
        max-width: 100vw !important;
    }
    #protections-popup-mainView {
        min-width: 100vw !important;
        max-width: 100vw !important;
    }
    #widget-overflow,
    #widget-overflow-mainView {
        height: calc(100vh - 80px) !important;
    }
    #customizationui-widget-panel {
        width: 100vw !important;
    }
    #BMB_bookmarksPopup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }

    /* Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }
    #customizationui-widget-panel {
        padding-left: 10px !important;
        padding-right: 10px !important;
    }
    #allTabsMenu-multiView box.panel-viewstack {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: 330px !important;
        max-height: 330px !important;
    }
    #allTabsMenu-allTabsViewTabs,
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 30px);
        padding-top: 2px !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Nav Bar */
    #back-button,
    #forward-button,
    #customizableui-special-spring1,
    #customizableui-special-spring2,
    #library-button,
    #sidebar-button,
    #fxa-toolbar-menu-button {
        display: none !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar {
        padding: 0px 5px;
    }
    #urlbar-input {
        font-size: 10pt !important;
    }
    #urlbar[focused] #urlbar-input {
        font-size: calc(var(--urlbar-height) - 9px) !important;
    }
    #urlbar[focused] #remote-control-box,
    #urlbar[focused] #identity-box,
    #urlbar[focused] #tracking-protection-icon-container,
    #urlbar[focused] #reader-mode-button,
    #urlbar[focused] #page-action-buttons,
    #tracking-protection-icon-container,
    #identity-permission-box,
    #userContext-indicator,
    #pageActionButton {
        display: none;
    }
    #identity-icon-label {
        display: none;
    }
    .urlbarView {
        position: fixed !important;
        inset: 0px 0px 84px 0px;
        width: 100% !important;
        background: var(--arrowpanel-background);
        margin: 0px !important;
        margin-inline: 0px !important;
        border-inline: 0px !important;
        overflow-y:  auto !important;
        overflow-x: none !important;
        scrollbar-width: none;
    }
    #PersonalToolbar {
        display: none;
    }
    :root {
        --bookmarks-toolbar-overlapping-browser-height: 0 !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering for Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 325px !important;
        max-height: 325px !important;
        width: calc(100vw - 30px) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

}

fenix_fox.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Resist Fingerprinting Letterbox background color and minimum width for display and URL Bar */
:root {
    --tabpanel-background-color: black !important;
    min-width: 300px !important;
}
#urlbar-container {
    min-width: 150px !important;
    flex-shrink: 1 !important;
}

/* Menu Bar color
   (hides the line at the top/bottom of the screen when Menubar is hidden) */
toolbar[type=menubar] {
    background-color: black !important;
    color: var(--toolbar-color) !important;
}

/* Nav Bar bottom border color */
#navigator-toolbox {
    border-bottom-color: black !important;
}

/* Remove popup warning when enterimg Fullscreen */
.pointerlockfswarning {
    display: none !important;
}

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Show Tab Manager Menu button */
#alltabs-button {
    display: -moz-box !important;
}

/* Tab Manager Menu button tab counter */
#TabsToolbar-customization-target {
    counter-reset: tabCount;
}
.tabbrowser-tab {
    counter-increment: tabCount;
}
#alltabs-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
    visibility: collapse !important;
}
#alltabs-button > .toolbarbutton-badge-stack {
     position: relative !important;
}
#alltabs-button > .toolbarbutton-badge-stack::before {
    content: counter(tabCount);
    color: var(--toolbarbutton-icon-fill);
    opacity: var(--toolbarbutton-icon-fill-opacity);
    position: absolute;
    bottom: var(--toolbarbutton-inner-padding);
    left: 50%;
    transform: translateX(-50%);
}
#alltabs-button > .toolbarbutton-badge-stack {
    border-radius: var(--toolbarbutton-border-radius);
}

/* Tab Manager Menu tab counter */
#allTabsMenu-allTabsViewTabs, /* before FF 106 */
#allTabsMenu-allTabsView-tabs { /* since FF 106 */
    counter-reset: nn_tabs 0 !important;
}
.all-tabs-button::before {
    display: -moz-inline-box !important;
    -moz-padding-end: 8px !important;
    content: counter(nn_tabs) !important;
    font-size: 12px !important; 
    margin-top: -2px !important; 
    margin-right: -2px !important;
}
.all-tabs-item {
    counter-increment: nn_tabs !important;
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Move Nav Bar to bottom */
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar*/
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --widget-overflow-margin: 22px;
        --unified-extensions-panel-margin: 22px;
        --customizationui-widget-panel-margin: 22px;
        --appMenu-popup-margin: 22px;
        --BMB_bookmarksPopup-margin: 22px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --widget-overflow-margin: 23px;
        --unified-extensions-panel-margin: 23px;
        --customizationui-widget-panel-margin: 23px;
        --appMenu-popup-margin: 23px;
        --BMB_bookmarksPopup-margin: 23px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        height: 340px;
        max-height: 340px;
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 4px !important;
        height: 318px !important;
        max-height: 318px !important;
        width: 230px !important;
    }
    #appMenu-multiView box.panel-viewstack:first-child {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Move Nav Bar to bottom */
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Adjust Widget Overflow Menu (») spawn height */
    #widget-overflow {
        margin-bottom: var(--widget-overflow-margin) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Adjust Main App Menu (≡) spawn height */
    #appMenu-popup {
        margin-bottom: var(--appMenu-popup-margin) !important;
    }

    /* Adjust Bookmarks Menu (★) spawn height */
    #BMB_bookmarksPopup {
        margin-bottom: var(--BMB_bookmarksPopup-margin) !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        margin-bottom: 225px !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar */
    .findbar-container {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        height: 40px !important;
    }
    .findbar-textbox {
        width: 100% !important;
    }
    .findbar-container checkbox {
        padding: 10px 0px;
    }
    .findbar-highlight,
    .findbar-case-sensitive,
    .findbar-match-diacritics,
    .findbar-entire-word,
    /*.found-matches,*/
    .findbar-find-status,
    .find-status-icon {
        display: none;
    }
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Fix Popups */
    #notification-popup {
        margin-top: -500px !important;
        margin-right: -500px !important;
        height: calc(100vh - 250px) !important;
        max-width: 100vw !important;
    }
    #downloadsPanel-mainView {
        max-width: calc(100vw - 10px);
    }
    #backForwardMenu {
        margin-top: -250px;
        height: 200px;
        min-height: 200px;
        max-width: 100vw !important;
    }
    #context-inspect,
    #context-inspect-a11y,
    #context-savelinktopocket,
    #context-searchselect,
    #context-sendlinktodevice,
    #context-viewpartialsource-selection,
    #inspect-separator {
        display: none !important
    }
    #protections-popup,
    #permission-popup,
    #widget-overflow,
    #identity-popup {
        max-width: 100vw !important;
    }
    #protections-popup-mainView {
        min-width: 100vw !important;
        max-width: 100vw !important;
    }
    #widget-overflow,
    #widget-overflow-mainView {
        height: calc(100vh - 80px) !important;
    }
    #customizationui-widget-panel {
        width: 100vw !important;
    }
    #BMB_bookmarksPopup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }

    /* Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }
    #customizationui-widget-panel {
        padding-left: 10px !important;
        padding-right: 10px !important;
    }
    #allTabsMenu-multiView box.panel-viewstack {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: 330px !important;
        max-height: 330px !important;
    }
    #allTabsMenu-allTabsViewTabs,
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 30px);
        padding-top: 2px !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Nav Bar */
    #back-button,
    #forward-button,
    #customizableui-special-spring1,
    #customizableui-special-spring2,
    #library-button,
    #sidebar-button,
    #fxa-toolbar-menu-button {
        display: none !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar {
        padding: 0px 5px;
    }
    #urlbar-input {
        font-size: 10pt !important;
    }
    #urlbar[focused] #urlbar-input {
        font-size: calc(var(--urlbar-height) - 9px) !important;
    }
    #urlbar[focused] #remote-control-box,
    #urlbar[focused] #identity-box,
    #urlbar[focused] #tracking-protection-icon-container,
    #urlbar[focused] #reader-mode-button,
    #urlbar[focused] #page-action-buttons,
    #tracking-protection-icon-container,
    #identity-permission-box,
    #userContext-indicator,
    #pageActionButton {
        display: none;
    }
    #identity-icon-label {
        display: none;
    }
    .urlbarView {
        position: fixed !important;
        inset: 0px 0px 84px 0px;
        width: 100% !important;
        background: var(--arrowpanel-background);
        margin: 0px !important;
        margin-inline: 0px !important;
        border-inline: 0px !important;
        overflow-y:  auto !important;
        overflow-x: none !important;
        scrollbar-width: none;
    }
    #PersonalToolbar {
        display: none;
    }
    :root {
        --bookmarks-toolbar-overlapping-browser-height: 0 !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering for Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 325px !important;
        max-height: 325px !important;
        width: calc(100vw - 30px) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

}

Note:

• fenix_fox-alt.css is a combination of the following files:

  • root.css
  • custom_rules.css
  • fenix-alt.css
  • true_mobile_landscape-alt.css
  • appMenu.css
  • editBookmarkPanel.css
  • findbar.css
  • popups.css
  • tabmenu.css
  • urlbar.css
  • extensions_menu.css
  • tab_counter.css

• fenix_fox.css is a combination of the following files:

  • root.css
  • custom_rules.css
  • fenix.css
  • true_mobile_landscape.css
  • appMenu.css
  • alt-browser-alt.css
  • editBookmarkPanel.css
  • findbar.css
  • popups.css
  • tabmenu.css
  • urlbar.css
  • extensions_menu.css
  • tab_counter.css

[Emma]

Fenix One (alt):

fenix_one-alt.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Resist Fingerprinting Letterbox background color and minimum width for display and URL Bar */
:root {
    --tabpanel-background-color: black !important;
    min-width: 300px !important;
}
#urlbar-container {
    min-width: 150px !important;
    flex-shrink: 1 !important;
}

/* Menu Bar color
   (hides the line at the top/bottom of the screen when Menubar is hidden) */
toolbar[type=menubar] {
    background-color: black !important;
    color: var(--toolbar-color) !important;
}

/* Nav Bar bottom border color */
#navigator-toolbox {
    border-bottom-color: black !important;
}

/* Remove popup warning when enterimg Fullscreen */
.pointerlockfswarning {
    display: none !important;
}

/* Fenix Colors */
:root {
    /* Popup panels */
    --arrowpanel-background: rgb(41,29,79) !important;
    --arrowpanel-border-color: transparent !important;
    --arrowpanel-color: white !important;
    --arrowpanel-dimmed: rgb(97,84,124) !important;
    --arrowpanel-dimmed-further: rgb(66,50,98) !important;
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
    --panel-item-hover-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-item-active-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-banner-item-background-color: rgb(117,66,228) !important;
    --panel-banner-item-hover-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-active-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-update-supported-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-info-icon-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-color: white !important;
    --panel-description-color: white !important;
    --panel-disabled-color: gray !important;
    --menuitem-disabled-hover-background-color: transparent !important;

    /* window and toolbar background */
    --lwt-accent-color: rgb(117,66,228) !important;
    --lwt-accent-color-inactive: rgba(117,66,228,0.3) !important;
    --toolbar-non-lwt-bgcolor: rgb(41,29,79) !important;
    --toolbar-non-lwt-textcolor: white !important;
    --toolbar-bgcolor: rgb(43,42,51) !important;
    --toolbar-color: rgb(171,113,255) !important;
    --tabpanel-background-color: black !important;

    /* tabs with system theme - text is not controlled by variable */
    --tab-selected-bgcolor: rgb(117,66,228) !important;

    /* tabs with any other theme */
    --lwt-text-color: white !important;
    --lwt-selected-tab-background-color: rgb(117,66,228) !important;

    /* toolbar area */
    --toolbarbutton-icon-fill: white !important;
    --toolbarbutton-icon-fill-attention: white !important;
    --toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-icon-fill-attention: white !important;
    --lwt-toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --toolbarseparator-color: black !important;

    /* urlbar */
    --toolbar-field-border-color: rgb(28,27,34) !important;
    --toolbar-field-focus-border-color: rgb(28,27,34) !important;
    --urlbar-popup-url-color: white !important;
    --urlbar-box-bgcolor: var(--button-bgcolor);
    --urlbar-box-focus-bgcolor: var(--button-bgcolor);
    --urlbar-box-hover-bgcolor: var(--button-hover-bgcolor);
    --urlbar-box-active-bgcolor: var(--button-active-bgcolor);
    --urlbar-box-text-color: inherit;
    --urlbar-box-hover-text-color: var(--urlbar-box-text-color);
    --lwt-brighttext-url-color: #00ddff;

    /* urlbar Firefox < 92 */
    --lwt-toolbar-field-background-color: rgb(28,27,34) !important;
    --lwt-toolbar-field-focus: white !important;
    --lwt-toolbar-field-color: white !important;
    --lwt-toolbar-field-focus-color: white !important;

    /* urlbar Firefox 92+ */
    --toolbar-field-background-color: rgb(28,27,34) !important;
    --toolbar-field-focus-background-color: rgb(28,27,34) !important;
    --toolbar-field-icon-fill-attention: rgb(117,66,228) !important;
    --toolbar-field-color: white !important;
    --toolbar-field-focus-color: white !important;

    /* sidebar - note the sidebar-box rule for the header-area */
    --lwt-sidebar-background-color: rgb(41,29,79) !important;
    --lwt-sidebar-text-color: white !important;

    /* findbar */
    --focus-outline-color: rgb(117,66,228) !important;
    --input-border-color: rgb(117,66,228) !important;

    /* buttons and checkboxes */
    --button-bgcolor: rgb(117,66,228) !important;
    --button-color: white !important;
    --button-hover-bgcolor: rgb(144,89,255) !important;
    --button-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-bgcolor: rgb(117,66,228) !important;
    --button-primary-hover-bgcolor: rgb(144,89,255) !important;
    --button-primary-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-color: white !important;
    --in-content-primary-button-background: rgb(117,66,228) !important;
    --in-content-primary-button-background-hover: rgb(144,89,255) !important;
    --in-content-primary-button-background-active: rgb(144,89,255) !important;
    --buttons-destructive-bgcolor: #e22850;
    --buttons-destructive-hover-bgcolor: #c50042;
    --buttons-destructive-active-bgcolor: #810220;
    --buttons-destructive-color: #fbfbfe;
    --checkbox-unchecked-bgcolor: rgb(41,29,79) !important;
    --checkbox-unchecked-hover-bgcolor: rgb(144,89,255) !important;
    --checkbox-unchecked-active-bgcolor: rgb(144,89,255) !important;
    --checkbox-checked-border-color: rgb(117,66,228) !important;
    --checkbox-checked-bgcolor: rgb(117,66,228) !important;
    --checkbox-checked-color: white !important;
    --checkbox-checked-hover-bgcolor: rgba(144,89,255) !important;
    --checkbox-checked-active-bgcolor: rgba(144,89,255) !important;
    --uc-checkbox-checked-bgcolor: rgb(117,66,228) !important;

    /* icon glow */
    --uc-icon-glow-primary: rgb(117,66,228);
    --uc-icon-glow-secondary: white;
    --uc-icon-glow-hover-primary: rgb(117,66,228);
    --uc-icon-glow-hover-secondary: white;
}

/* line between nav-bar and tabs toolbar,
        also fallback color for border around selected tab */
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(65,64,72) !important;
}

/* Line above tabs */
#tabbrowser-tabs {
    --lwt-tab-line-color: none !important;
}

/* the header-area of sidebar needs this to work */
#sidebar-box {
    --sidebar-background-color: rgb(41,29,79) !important;
}

/* Find Bar */
.findbar-find-previous,
.findbar-find-next,
input.findbar-textbox,
findbar {
    border: none !important;
    box-shadow: none !important;
    background-color: var(--arrowpanel-background) !important;
    color: var(--toolbar-field-color) !important;
}

/* Context Menus */
menupopup {
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
}
menuseparator {
    display: none !important;
}
menu:hover,
menuitem:hover {
    background-color: var(--panel-item-hover-bgcolor) !important;
    color: var(--panel-color) !important;
}

/* Menu popup shadow */
.menupopup-arrowscrollbox {
    box-shadow: 0 5px 5px -3px rgba(0,0,0,0.2),
                0 8px 10px 1px rgba(0,0,0,0.14),
                0 3px 14px 2px rgba(0,0,0,0.12) !important;
}

/* "Saved to Library!" popup notification */
#confirmation-hint {
    --panel-background: var(--lwt-accent-color) !important;
    --panel-border-color: var(--lwt-accent-color) !important;
    --panel-color: var(--lwt-text-color) !important;
}

/* "Confirm before closing multiple tabs" popup checkboxes and dialog buttons */
.checkbox-check {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}
.dialog-button-box > button:nth-child(6) {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}

/* Main App Menu (≡), Tab Manager Menu, and Unified Extensions Menu */
panel {
    --panel-background: black !important;
    --panel-shadow: none !important;
}
.panel-viewstack {
    background-color: var(--arrowpanel-background) !important;
    border-color: var(--arrowpanel-background) !important;
}

/* Tab Manager Menu */
#allTabsMenu-allTabsView-tabs,
#allTabsMenu-allTabsView,
#allTabsMenu-containerTabsView {
    background-color: var(--toolbar-bgcolor) !important;
}
#allTabsMenu-containerTabsButton,
#allTabsMenu-containerTabsView > .panel-header {
    color: var(--toolbar-color) !important;
}
#allTabsMenu-containerTabsButton:hover {
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-item[selected] {
    background-color: var(--arrowpanel-dimmed-further) !important;
}
.all-tabs-item:hover[selected] {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--arrowpanel-dimmed) !important;
}
.all-tabs-item:hover:not([selected]) {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-close-button:hover {
    background-color: var(--toolbarbutton-hover-background) !important;
}

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Tab Manager Menu button tab counter */
#alltabs-button {
    display: -moz-box !important;
}
#TabsToolbar-customization-target {
    counter-reset: tabCount;
}
.tabbrowser-tab {
    counter-increment: tabCount;
}
#alltabs-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
    visibility: collapse !important;
}
#alltabs-button > .toolbarbutton-badge-stack {
     position: relative !important;
}
#alltabs-button > .toolbarbutton-badge-stack::before {
    content: counter(tabCount);
    color: var(--toolbarbutton-icon-fill);
    opacity: var(--toolbarbutton-icon-fill-opacity);
    position: absolute;
    bottom: var(--toolbarbutton-inner-padding);
    left: 50%;
    transform: translateX(-50%);
}
#alltabs-button > .toolbarbutton-badge-stack {
    border-radius: var(--toolbarbutton-border-radius);
}

/* Tab Manager Menu tab counter */
#allTabsMenu-allTabsViewTabs, /* before FF 106 */
#allTabsMenu-allTabsView-tabs { /* since FF 106 */
    counter-reset: nn_tabs 0 !important;
}
.all-tabs-button::before {
    display: -moz-inline-box !important;
    -moz-padding-end: 8px !important;
    content: counter(nn_tabs) !important;
    font-size: 12px !important; 
    margin-top: -2px !important; 
    margin-right: -2px !important;
}
.all-tabs-item {
    counter-increment: nn_tabs !important;
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar*/
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 4px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        height: 340px;
        max-height: 340px;
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 4px !important;
        height: 318px !important;
        max-height: 318px !important;
        width: 230px !important;
    }
    #appMenu-multiView box.panel-viewstack:first-child {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        margin-bottom: 225px !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar */
    .findbar-container {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        height: 40px !important;
    }
    .findbar-textbox {
        width: 100% !important;
    }
    .findbar-container checkbox {
        padding: 10px 0px;
    }
    .findbar-highlight,
    .findbar-case-sensitive,
    .findbar-match-diacritics,
    .findbar-entire-word,
    /*.found-matches,*/
    .findbar-find-status,
    .find-status-icon {
        display: none;
    }
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Fix Popups */
    #notification-popup {
        margin-top: -500px !important;
        margin-right: -500px !important;
        height: calc(100vh - 250px) !important;
        max-width: 100vw !important;
    }
    #downloadsPanel-mainView {
        max-width: calc(100vw - 10px);
    }
    #backForwardMenu {
        margin-top: -250px;
        height: 200px;
        min-height: 200px;
        max-width: 100vw !important;
    }
    #context-inspect,
    #context-inspect-a11y,
    #context-savelinktopocket,
    #context-searchselect,
    #context-sendlinktodevice,
    #context-viewpartialsource-selection,
    #inspect-separator {
        display: none !important
    }
    #protections-popup,
    #permission-popup,
    #widget-overflow,
    #identity-popup {
        max-width: 100vw !important;
    }
    #protections-popup-mainView {
        min-width: 100vw !important;
        max-width: 100vw !important;
    }
    #widget-overflow,
    #widget-overflow-mainView {
        height: calc(100vh - 80px) !important;
    }
    #customizationui-widget-panel {
        width: 100vw !important;
    }
    #BMB_bookmarksPopup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }

    /* Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }
    #customizationui-widget-panel {
        padding-left: 10px !important;
        padding-right: 10px !important;
    }
    #allTabsMenu-multiView box.panel-viewstack {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: 330px !important;
        max-height: 330px !important;
    }
    #allTabsMenu-allTabsViewTabs,
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 30px);
        padding-top: 2px !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        top: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Nav Bar */
    #back-button,
    #forward-button,
    #customizableui-special-spring1,
    #customizableui-special-spring2,
    #library-button,
    #sidebar-button,
    #fxa-toolbar-menu-button {
        display: none !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar {
        padding: 0px 5px;
    }
    #urlbar-input {
        font-size: 10pt !important;
    }
    #urlbar[focused] #urlbar-input {
        font-size: calc(var(--urlbar-height) - 9px) !important;
    }
    #urlbar[focused] #remote-control-box,
    #urlbar[focused] #identity-box,
    #urlbar[focused] #tracking-protection-icon-container,
    #urlbar[focused] #reader-mode-button,
    #urlbar[focused] #page-action-buttons,
    #tracking-protection-icon-container,
    #identity-permission-box,
    #userContext-indicator,
    #pageActionButton {
        display: none;
    }
    #identity-icon-label {
        display: none;
    }
    .urlbarView {
        position: fixed !important;
        inset: 0px 0px 84px 0px;
        width: 100% !important;
        background: var(--arrowpanel-background);
        margin: 0px !important;
        margin-inline: 0px !important;
        border-inline: 0px !important;
        overflow-y:  auto !important;
        overflow-x: none !important;
        scrollbar-width: none;
    }
    #PersonalToolbar {
        display: none;
    }
    :root {
        --bookmarks-toolbar-overlapping-browser-height: 0 !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering for Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 325px !important;
        max-height: 325px !important;
        width: calc(100vw - 30px) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

}

/* Private Browsing Mode theme for URL Bar and Nav Bar */
:root {
    --toolbar-field-border-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-border-color: var(--arrowpanel-background) !important;
    --lwt-toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-background-color: var(--arrowpanel-background) !important;
}
#nav-bar {
    background-image: -moz-linear-gradient(to right, rgb(112,34,145), rgb(57,52,115)) !important;
}
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(134,93,180) !important;
}

Note:

• fenix_one-alt.css is a combination of the following files:

  • fenix_colors.css
  • fenix_fox-alt.css

[Emma]

Fenix One:

fenix_one.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/******************************************/
/*               IMPORTANT:               */
/*                                        */
/* One of the things this code will do is */
/* to move the Tab Manager Menu button to */
/* the right side of the URL Bar.         */
/*                                        */
/* For the best results, consider moving  */
/* the Unified Extensions Menu button to  */
/* the left of the URL Bar and removing   */
/* less important toolbar items by using  */
/* the "Customize Toolbar" feature, or by */
/* using a user.js file in your profile.  */
/******************************************/

/* Resist Fingerprinting Letterbox background color and minimum width for display and URL Bar */
:root {
    --tabpanel-background-color: black !important;
    min-width: 300px !important;
}
#urlbar-container {
    min-width: 150px !important;
    flex-shrink: 1 !important;
}

/* Menu Bar color
   (hides the line at the top/bottom of the screen when Menubar is hidden) */
toolbar[type=menubar] {
    background-color: black !important;
    color: var(--toolbar-color) !important;
}

/* Nav Bar bottom border color */
#navigator-toolbox {
    border-bottom-color: black !important;
}

/* Remove popup warning when enterimg Fullscreen */
.pointerlockfswarning {
    display: none !important;
}

/* Fenix Colors */
:root {
    /* Popup panels */
    --arrowpanel-background: rgb(41,29,79) !important;
    --arrowpanel-border-color: transparent !important;
    --arrowpanel-color: white !important;
    --arrowpanel-dimmed: rgb(97,84,124) !important;
    --arrowpanel-dimmed-further: rgb(66,50,98) !important;
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
    --panel-item-hover-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-item-active-bgcolor: rgba(255,255,255,0.2) !important;
    --panel-banner-item-background-color: rgb(117,66,228) !important;
    --panel-banner-item-hover-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-active-bgcolor: rgb(69,68,76) !important;
    --panel-banner-item-update-supported-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-info-icon-bgcolor: rgb(117,66,228) !important;
    --panel-banner-item-color: white !important;
    --panel-description-color: white !important;
    --panel-disabled-color: gray !important;
    --menuitem-disabled-hover-background-color: transparent !important;

    /* window and toolbar background */
    --lwt-accent-color: rgb(117,66,228) !important;
    --lwt-accent-color-inactive: rgba(117,66,228,0.3) !important;
    --toolbar-non-lwt-bgcolor: rgb(41,29,79) !important;
    --toolbar-non-lwt-textcolor: white !important;
    --toolbar-bgcolor: rgb(43,42,51) !important;
    --toolbar-color: rgb(171,113,255) !important;
    --tabpanel-background-color: black !important;

    /* tabs with system theme - text is not controlled by variable */
    --tab-selected-bgcolor: rgb(117,66,228) !important;

    /* tabs with any other theme */
    --lwt-text-color: white !important;
    --lwt-selected-tab-background-color: rgb(117,66,228) !important;

    /* toolbar area */
    --toolbarbutton-icon-fill: white !important;
    --toolbarbutton-icon-fill-attention: white !important;
    --toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-icon-fill-attention: white !important;
    --lwt-toolbarbutton-hover-background: rgba(255,255,255,0.2) !important;
    --lwt-toolbarbutton-active-background: rgba(255,255,255,0.2) !important;
    --toolbarseparator-color: black !important;

    /* urlbar */
    --toolbar-field-border-color: rgb(28,27,34) !important;
    --toolbar-field-focus-border-color: rgb(28,27,34) !important;
    --urlbar-popup-url-color: white !important;
    --urlbar-box-bgcolor: var(--button-bgcolor);
    --urlbar-box-focus-bgcolor: var(--button-bgcolor);
    --urlbar-box-hover-bgcolor: var(--button-hover-bgcolor);
    --urlbar-box-active-bgcolor: var(--button-active-bgcolor);
    --urlbar-box-text-color: inherit;
    --urlbar-box-hover-text-color: var(--urlbar-box-text-color);
    --lwt-brighttext-url-color: #00ddff;

    /* urlbar Firefox < 92 */
    --lwt-toolbar-field-background-color: rgb(28,27,34) !important;
    --lwt-toolbar-field-focus: white !important;
    --lwt-toolbar-field-color: white !important;
    --lwt-toolbar-field-focus-color: white !important;

    /* urlbar Firefox 92+ */
    --toolbar-field-background-color: rgb(28,27,34) !important;
    --toolbar-field-focus-background-color: rgb(28,27,34) !important;
    --toolbar-field-icon-fill-attention: rgb(117,66,228) !important;
    --toolbar-field-color: white !important;
    --toolbar-field-focus-color: white !important;

    /* sidebar - note the sidebar-box rule for the header-area */
    --lwt-sidebar-background-color: rgb(41,29,79) !important;
    --lwt-sidebar-text-color: white !important;

    /* findbar */
    --focus-outline-color: rgb(117,66,228) !important;
    --input-border-color: rgb(117,66,228) !important;

    /* buttons and checkboxes */
    --button-bgcolor: rgb(117,66,228) !important;
    --button-color: white !important;
    --button-hover-bgcolor: rgb(144,89,255) !important;
    --button-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-bgcolor: rgb(117,66,228) !important;
    --button-primary-hover-bgcolor: rgb(144,89,255) !important;
    --button-primary-active-bgcolor: rgb(144,89,255) !important;
    --button-primary-color: white !important;
    --in-content-primary-button-background: rgb(117,66,228) !important;
    --in-content-primary-button-background-hover: rgb(144,89,255) !important;
    --in-content-primary-button-background-active: rgb(144,89,255) !important;
    --buttons-destructive-bgcolor: #e22850;
    --buttons-destructive-hover-bgcolor: #c50042;
    --buttons-destructive-active-bgcolor: #810220;
    --buttons-destructive-color: #fbfbfe;
    --checkbox-unchecked-bgcolor: rgb(41,29,79) !important;
    --checkbox-unchecked-hover-bgcolor: rgb(144,89,255) !important;
    --checkbox-unchecked-active-bgcolor: rgb(144,89,255) !important;
    --checkbox-checked-border-color: rgb(117,66,228) !important;
    --checkbox-checked-bgcolor: rgb(117,66,228) !important;
    --checkbox-checked-color: white !important;
    --checkbox-checked-hover-bgcolor: rgba(144,89,255) !important;
    --checkbox-checked-active-bgcolor: rgba(144,89,255) !important;
    --uc-checkbox-checked-bgcolor: rgb(117,66,228) !important;

    /* icon glow */
    --uc-icon-glow-primary: rgb(117,66,228);
    --uc-icon-glow-secondary: white;
    --uc-icon-glow-hover-primary: rgb(117,66,228);
    --uc-icon-glow-hover-secondary: white;
}

/* line between nav-bar and tabs toolbar,
        also fallback color for border around selected tab */
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(65,64,72) !important;
}

/* Line above tabs */
#tabbrowser-tabs {
    --lwt-tab-line-color: none !important;
}

/* the header-area of sidebar needs this to work */
#sidebar-box {
    --sidebar-background-color: rgb(41,29,79) !important;
}

/* Find Bar */
.findbar-find-previous,
.findbar-find-next,
input.findbar-textbox,
findbar {
    border: none !important;
    box-shadow: none !important;
    background-color: var(--arrowpanel-background) !important;
    color: var(--toolbar-field-color) !important;
}

/* Context Menus */
menupopup {
    --panel-background: rgb(41,29,79) !important;
    --panel-border-color: transparent !important;
    --panel-color: white !important;
    --panel-separator-color: transparent !important;
}
menuseparator {
    display: none !important;
}
menu:hover,
menuitem:hover {
    background-color: var(--panel-item-hover-bgcolor) !important;
    color: var(--panel-color) !important;
}

/* Menu popup shadow */
.menupopup-arrowscrollbox {
    box-shadow: 0 5px 5px -3px rgba(0,0,0,0.2),
                0 8px 10px 1px rgba(0,0,0,0.14),
                0 3px 14px 2px rgba(0,0,0,0.12) !important;
}

/* "Saved to Library!" popup notification */
#confirmation-hint {
    --panel-background: var(--lwt-accent-color) !important;
    --panel-border-color: var(--lwt-accent-color) !important;
    --panel-color: var(--lwt-text-color) !important;
}

/* "Confirm before closing multiple tabs" popup checkboxes and dialog buttons */
.checkbox-check {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}
.dialog-button-box > button:nth-child(6) {
    background-color: var(--buttons-destructive-bgcolor) !important;
    color: var(--buttons-destructive-color) !important;
}

/* Main App Menu (≡), Tab Manager Menu, and Unified Extensions Menu */
panel {
    --panel-background: black !important;
    --panel-shadow: none !important;
}
.panel-viewstack {
    background-color: var(--arrowpanel-background) !important;
    border-color: var(--arrowpanel-background) !important;
}

/* Tab Manager Menu */
#allTabsMenu-allTabsView-tabs,
#allTabsMenu-allTabsView,
#allTabsMenu-containerTabsView {
    background-color: var(--toolbar-bgcolor) !important;
}
#allTabsMenu-containerTabsButton,
#allTabsMenu-containerTabsView > .panel-header {
    color: var(--toolbar-color) !important;
}
#allTabsMenu-containerTabsButton:hover {
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-item[selected] {
    background-color: var(--arrowpanel-dimmed-further) !important;
}
.all-tabs-item:hover[selected] {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--arrowpanel-dimmed) !important;
}
.all-tabs-item:hover:not([selected]) {
    --panel-item-active-bgcolor: transparent !important;
    --panel-item-hover-bgcolor: transparent !important;
    background-color: var(--panel-banner-item-hover-bgcolor) !important;
}
.all-tabs-close-button:hover {
    background-color: var(--toolbarbutton-hover-background) !important;
}

/* Main App Menu (≡) item icons */
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before,
#appMenu-protonMainView > .panel-subview-body > toolbarbutton > image {
  fill: currentColor;
  -moz-context-properties: fill;
  margin-inline: 0 20px !important;
}
#appMenu-zoom-controls::before,
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
  display: flex;
  content: "";
  width: 16px;
  height: 16px;
}
#appMenu-new-tab-button2 {
    order: 1 !important;
    list-style-image: url("chrome://global/skin/icons/plus.svg");
}
#appMenu-bookmarks-button {
    order: 2 !important;
    list-style-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
}
#appMenu-history-button {
    order: 3 !important;
    list-style-image: url("chrome://browser/skin/history.svg");
}
#appMenu-downloads-button {
    order: 4 !important;
    list-style-image: url("chrome://browser/skin/downloads/downloads.svg");
}
#appMenu-extensions-themes-button {
    order: 5 !important;
    list-style-image: url("chrome://mozapps/skin/extensions/extension.svg");
}
#appMenu-passwords-button {
    order: 6 !important;
    list-style-image: url("chrome://browser/skin/login.svg");
}
#appMenu-find-button2 {
    order: 7 !important;
    list-style-image: url("chrome://global/skin/icons/search-glass.svg");
}
#appMenu-zoom-controls {
    order: 8 !important;
}
#appMenu-zoom-controls::before {
    background-image: url("chrome://browser/skin/fullscreen.svg");
}
#appMenu-new-window-button2 {
    order: 9 !important;
    list-style-image: url("chrome://browser/skin/window.svg");
}
#appMenu-new-private-window-button2 {
    order: 10 !important;
    list-style-image: url("chrome://browser/skin/privateBrowsing.svg");
}
#appMenu-save-file-button2 {
    order: 11 !important;
    list-style-image: url("chrome://browser/skin/save.svg");
}
#appMenu-print-button2 {
    order: 12 !important;
    list-style-image: url("chrome://global/skin/icons/print.svg");
}
#appMenu-help-button2 {
    order: 13 !important;
    list-style-image: url("chrome://global/skin/icons/help.svg");
}
#appMenu-more-button2 {
    order: 14 !important;
    list-style-image: url("chrome://global/skin/icons/developer.svg");
}
#appMenu-settings-button {
    order: 15 !important;
    list-style-image: url("chrome://global/skin/icons/settings.svg");
}
#appMenu-quit-button2 {
    order: 16 !important;
    list-style-image: url("chrome://devtools/skin/images/search-clear.svg");
}
/* Use account-button icon for signed in sync item */
#appMenu-fxa-status2[fxastatus] > toolbarbutton::before {
    background-image: var(--avatar-image-url)
}

/* Tab Manager Menu button tab counter */
#alltabs-button {
    display: -moz-box !important;
}
#TabsToolbar-customization-target {
    counter-reset: tabCount;
}
.tabbrowser-tab {
    counter-increment: tabCount;
}
#alltabs-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
    visibility: collapse !important;
}
#alltabs-button > .toolbarbutton-badge-stack {
     position: relative !important;
}
#alltabs-button > .toolbarbutton-badge-stack::before {
    content: counter(tabCount);
    color: var(--toolbarbutton-icon-fill);
    opacity: var(--toolbarbutton-icon-fill-opacity);
    position: absolute;
    bottom: var(--toolbarbutton-inner-padding);
    left: 50%;
    transform: translateX(-50%);
}
#alltabs-button > .toolbarbutton-badge-stack {
    border-radius: var(--toolbarbutton-border-radius);
}

/* Tab Manager Menu tab counter */
#allTabsMenu-allTabsViewTabs, /* before FF 106 */
#allTabsMenu-allTabsView-tabs { /* since FF 106 */
    counter-reset: nn_tabs 0 !important;
}
.all-tabs-button::before {
    display: -moz-inline-box !important;
    -moz-padding-end: 8px !important;
    content: counter(nn_tabs) !important;
    font-size: 12px !important; 
    margin-top: -2px !important; 
    margin-right: -2px !important;
}
.all-tabs-item {
    counter-increment: nn_tabs !important;
}

/* Apply this customization only on smaller screens in landscape mode */
@media (orientation: landscape) and (max-height: 650px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 188.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 196.5px);
    }

    /* Remove items from Main App Menu (≡) */
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Fix flickering of Main App Menu (≡) */
    #appMenu-popup {
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        height: 253px !important;
        max-height: 253px !important;
        width: 250px !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Move Nav Bar to bottom */
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar*/
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Remove items from Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }

    /* Fix flickering of Tab Manager Menu and extension popups */
    #customizationui-widget-panel,
    #customizationui-widget-multiview box.panel-viewstack {
        height: calc(100vh - 35px) !important;
        max-height: calc(100vh - 35px) !important;
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 18px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of URL Bar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering of Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        width: 360px !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 230px !important;
        max-height: 230px !important;
        width: 350px !important;
    }

    /* Add padding to bottom of Unified Extensions Menu to look better */
    #unified-extensions-area {
        padding-bottom: 5px !important;
    }

    /* Allow extensions to use full display */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: 100vw !important;
        min-width: 100vw !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

}

/* Apply this customization only on smaller screens in portrait mode */
@media (orientation: portrait) and (max-width: 720px) {

    /* Density variables */
    :root:not([uidensity="touch"]) {
        --PanelUI-menu-button-position: 4px;
        --widget-overflow-margin: 22px;
        --unified-extensions-panel-margin: 22px;
        --customizationui-widget-panel-margin: 22px;
        --appMenu-popup-margin: 22px;
        --BMB_bookmarksPopup-margin: 22px;
        --alltabs-button-height: 32px;
        --alltabs-button-width: 32px;
        --alltabs-button-position: 3.5px;
        --urlbar-width: calc(100vw - 110.5px);
    }
    :root[uidensity="touch"] {
        --PanelUI-menu-button-position: 5px;
        --widget-overflow-margin: 23px;
        --unified-extensions-panel-margin: 23px;
        --customizationui-widget-panel-margin: 23px;
        --appMenu-popup-margin: 23px;
        --BMB_bookmarksPopup-margin: 23px;
        --alltabs-button-height: 34px;
        --alltabs-button-width: 34px;
        --alltabs-button-position: 4.5px;
        --urlbar-width: calc(100vw - 114.5px);
    }

    /* Main App Menu (≡) */
    #appMenu-popup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        height: 340px;
        max-height: 340px;
        width: 260px !important;
    }
    #appMenu-protonMainView vbox.panel-subview-body {
        margin-top: 4px !important;
        height: 318px !important;
        max-height: 318px !important;
        width: 230px !important;
    }
    #appMenu-multiView box.panel-viewstack:first-child {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #appMenu-fxa-status2,
    #appMenu-fxa-separator,
    #appMenu-protonMainView toolbarseparator,
    #appMenu-fullscreen-button2,
    #appMenu-passwords-button,
    .subviewbutton[shortcut]::after {
        display: none !important;
    }

    /* Change Main App Menu (≡) button to its mobile equivalent (⋮) */
    #PanelUI-menu-button {
        position: absolute !important;
        right: 0px !important;
        bottom: var(--PanelUI-menu-button-position) !important;
        margin-right: -10px !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack > .toolbarbutton-icon {
        visibility: collapse !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack {
        position: relative !important;
        width: 75% !important;
    }
    #PanelUI-menu-button > .toolbarbutton-badge-stack::before {
        content: "⋮";
        color: var(--toolbarbutton-icon-fill);
        opacity: var(--toolbarbutton-icon-fill-opacity);
        position: absolute;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.9 );
        left: 50%;
        transform: translateX(-50%);
        font-size: 18px !important;
        font-weight: bold !important;
    }

    /* Hide Tab Bar and Private Browsing Indicator */
    #tabbrowser-tabs,
    #private-browsing-indicator-with-label {
        visibility: collapse !important;
    }

    /* Hide Nav Bar and Tab Bar when in Fullscreen mode and hide and Title Bar */
    #nav-bar[inFullscreen],
    #TabsToolbar[inFullscreen],
    .titlebar-buttonbox-container {
        display: none;
    }

    /* Move Nav Bar to bottom */
    :root:not([uidensity="touch"],[inFullscreen]) {
        --uc-bottom-toolbar-height: calc(39px + var(--toolbarbutton-outer-padding) )
    }
    :root[uidensity="touch"]:not([inFullscreen]){
        --uc-bottom-toolbar-height: calc(43px + var(--toolbarbutton-outer-padding) )
    }
    #browser,
    #customization-container {
        margin-bottom: var(--uc-bottom-toolbar-height,0px)
    }
    #nav-bar{
        position: fixed !important;
        bottom: 0px;
        width: 100%;
        z-index: 1;
    }
    .panel-viewstack {
        max-height: unset !important;
    }

    /* Adjust Widget Overflow Menu (») spawn height */
    #widget-overflow {
        margin-bottom: var(--widget-overflow-margin) !important;
    }

    /* Adjust Unified Extensions Menu spawn height */
    #unified-extensions-panel {
        margin-bottom: var(--unified-extensions-panel-margin) !important;
    }

    /* Adjust Tab Manager Menu spawn height */
    #customizationui-widget-panel {
        margin-bottom: var(--customizationui-widget-panel-margin) !important;
    }

    /* Adjust Main App Menu (≡) spawn height */
    #appMenu-popup {
        margin-bottom: var(--appMenu-popup-margin) !important;
    }

    /* Adjust Bookmarks Menu (★) spawn height */
    #BMB_bookmarksPopup {
        margin-bottom: var(--BMB_bookmarksPopup-margin) !important;
    }

    /* Edit Bookmark Panel */
    #editBookmarkPanel {
        background-color: var(--arrowpanel-background) !important;
        margin-bottom: 225px !important;
        max-height: 100vh !important;
        max-width: 100vw !important;
        width: 100vw !important;
    }
    #editBookmarkPanel box.panel-header,
    #editBookmarkHeaderSeparator,
    #editBookmarkPanelInfoArea,
    #editBookmarkSeparator,
    #editBMPanel_folderRow,
    #editBMPanel_tagsRow {
        display: none !important;
    }
    #editBookmarkPanelContent {
        padding-top: 0 !important;
        padding-bottom: 0 !important;
    }
    #editBookmarkPanelBottomButtons {
        margin-top: -5px !important;
        margin-left: -50px !important;
    }

    /* Find Bar */
    .findbar-container {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        height: 40px !important;
    }
    .findbar-textbox {
        width: 100% !important;
    }
    .findbar-container checkbox {
        padding: 10px 0px;
    }
    .findbar-highlight,
    .findbar-case-sensitive,
    .findbar-match-diacritics,
    .findbar-entire-word,
    /*.found-matches,*/
    .findbar-find-status,
    .find-status-icon {
        display: none;
    }
    input.findbar-textbox {
        font-size: 12pt !important;
    }

    /* Fix Popups */
    #notification-popup {
        margin-top: -500px !important;
        margin-right: -500px !important;
        height: calc(100vh - 250px) !important;
        max-width: 100vw !important;
    }
    #downloadsPanel-mainView {
        max-width: calc(100vw - 10px);
    }
    #backForwardMenu {
        margin-top: -250px;
        height: 200px;
        min-height: 200px;
        max-width: 100vw !important;
    }
    #context-inspect,
    #context-inspect-a11y,
    #context-savelinktopocket,
    #context-searchselect,
    #context-sendlinktodevice,
    #context-viewpartialsource-selection,
    #inspect-separator {
        display: none !important
    }
    #protections-popup,
    #permission-popup,
    #widget-overflow,
    #identity-popup {
        max-width: 100vw !important;
    }
    #protections-popup-mainView {
        min-width: 100vw !important;
        max-width: 100vw !important;
    }
    #widget-overflow,
    #widget-overflow-mainView {
        height: calc(100vh - 80px) !important;
    }
    #customizationui-widget-panel {
        width: 100vw !important;
    }
    #BMB_bookmarksPopup {
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }

    /* Tab Manager Menu */
    #allTabsMenu-searchTabs,
    #allTabsMenu-tabsSeparator {
        display: none;
    }
    #customizationui-widget-panel {
        padding-left: 10px !important;
        padding-right: 10px !important;
    }
    #allTabsMenu-multiView box.panel-viewstack {
        height: calc(100vh - 100px) !important;
        max-height: calc(100vh - 100px) !important;
    }
    #customizationui-widget-multiview box.panel-viewstack {
        height: 330px !important;
        max-height: 330px !important;
    }
    #allTabsMenu-allTabsViewTabs,
    #allTabsMenu-allTabsView-tabs {
        max-width: calc(100vw - 30px);
        padding-top: 2px !important;
    }

    /* Expand Tab Manager Menu */
    #customizationui-widget-multiview panelview {
        max-width: 100% !important;
        width: 100% !important;
    }

    /* Tab Manager Menu inspired by Firefox for Android */
    #allTabsMenu-containerTabsButton {
        border-radius: 0 !important;
        margin: 0 !important;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-item {
        border-radius: 0 !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(100vw - 30px) !important;
    }
    .all-tabs-close-button {
        border-radius: 100% !important;
        margin-left: calc(var(--urlbar-min-height) * -0.6 ) !important;
        margin-right: calc(var(--urlbar-min-height) * -0.6 ) !important;
        height: calc(var(--urlbar-min-height) * 2.25 ) !important;
        width: calc(var(--urlbar-min-height) * 2.25 ) !important;
    }
    .all-tabs-close-button > .toolbarbutton-icon {
        margin-left: calc(var(--urlbar-min-height) * 0.625 ) !important;
        height: calc(var(--urlbar-min-height) * 0.5 ) !important;
        width: calc(var(--urlbar-min-height) * 0.5 ) !important;
    }

    /* Tab Manager Menu button inspired by Firefox for Android */
    #alltabs-button > .toolbarbutton-badge-stack::before {
        border: 1px solid var(--toolbarbutton-icon-fill);
        border-radius: 2px;
        bottom: calc(var(--toolbarbutton-inner-padding) * 0.85 ) !important;
        padding: 0 5px 0 5px;
        font-size: 8px !important;
        font-weight: 600 !important;
        font-family: "Noto Sans" !important;
    }

    /* Move Tab Manager Menu button to right of urlbar */
    :root {
        --tab-border-radius: var(--toolbarbutton-border-radius) !important;
    }
    #alltabs-button > .toolbarbutton-badge-stack {
        height: var(--alltabs-button-height) !important;
        width: var(--alltabs-button-width) !important;
    }
    #alltabs-button {
        position: absolute;
        bottom: var(--alltabs-button-position) !important;
        right: 28.5px;
        z-index: 2 !important;
    }

    /* Nav Bar */
    #back-button,
    #forward-button,
    #customizableui-special-spring1,
    #customizableui-special-spring2,
    #library-button,
    #sidebar-button,
    #fxa-toolbar-menu-button {
        display: none !important;
    }

    /* Allow room for Tab Manager Menu button */
    #nav-bar {
        padding-right: 67px !important;
    }

    /* URL Bar */
    #urlbar-container {
        max-width: var(--urlbar-width) !important;
    }
    #urlbar {
        padding: 0px 5px;
    }
    #urlbar-input {
        font-size: 10pt !important;
    }
    #urlbar[focused] #urlbar-input {
        font-size: calc(var(--urlbar-height) - 9px) !important;
    }
    #urlbar[focused] #remote-control-box,
    #urlbar[focused] #identity-box,
    #urlbar[focused] #tracking-protection-icon-container,
    #urlbar[focused] #reader-mode-button,
    #urlbar[focused] #page-action-buttons,
    #tracking-protection-icon-container,
    #identity-permission-box,
    #userContext-indicator,
    #pageActionButton {
        display: none;
    }
    #identity-icon-label {
        display: none;
    }
    .urlbarView {
        position: fixed !important;
        inset: 0px 0px 84px 0px;
        width: 100% !important;
        background: var(--arrowpanel-background);
        margin: 0px !important;
        margin-inline: 0px !important;
        border-inline: 0px !important;
        overflow-y:  auto !important;
        overflow-x: none !important;
        scrollbar-width: none;
    }
    #PersonalToolbar {
        display: none;
    }
    :root {
        --bookmarks-toolbar-overlapping-browser-height: 0 !important;
    }
    #urlbar,
    #searchbar,
    #urlbar-input,
    #urlbar-input-container,
    #urlbar-background {
        border-radius: 7px !important;
    }

    /* Remove items from Unified Extensions Menu */
    #unified-extensions-panel .panel-header,
    #unified-extensions-panel toolbarseparator,
    #unified-extensions-manage-extensions {
        display: none !important;
    }

    /* Adjust button padding and font size for secondary text in Unified Extensions Menu */
    #unified-extensions-panel .subviewbutton {
        padding: 6px !important;
    }
    .unified-extensions-item-message {
        font-size: 75% !important;
    }

    /* Fix flickering for Unified Extensions Menu */
    #unified-extensions-panel {
        --uei-icon-size: 20px;
        padding-left: 10px !important;
        padding-right: 10px !important;
        width: 100vw !important;
    }
    #unified-extensions-view {
        margin-top: 6px !important;
        height: 325px !important;
        max-height: 325px !important;
        width: calc(100vw - 30px) !important;
    }

    /* Allow extensions to use full popup */
    .webextension-popup-browser {
        height: 100% !important;
        min-height: 100% !important;
        width: calc(100vw - 20px) !important;
        min-width: calc(100vw - 20px) !important;
    }

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

    /* Adjust "Saved to Library!" popup notification */
    #confirmation-hint {
        padding: 10px !important;
        width: 100vw !important;
    }

    /* Adjust "Confirm before closing multiple tabs" popup */
    .dialogFrame {
        width: 100vw !important;
        max-width: 100vw !important;
    }

    /* Added extra space to bottom of Unified Extensions Menu to compensate for orientation problem that would leave some extensions hidden in portrait mode when Unified Extentions Menu is first opened in landscape mode */
    #unified-extensions-area {
        padding-bottom: 120px !important;
    }

    /* Added extra space to bottom of Main App Menu (≡) to compensate for orientation problem that would leave some items hidden in portrait mode when Main App Menu (≡) is first opened in landscape mode */
    #appMenu-quit-button2 {
        margin-bottom: 64px !important;
    }

}

/* Private Browsing Mode theme for URL Bar and Nav Bar */
:root {
    --toolbar-field-border-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-border-color: var(--arrowpanel-background) !important;
    --lwt-toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-background-color: var(--arrowpanel-background) !important;
}
#nav-bar {
    background-image: -moz-linear-gradient(to right, rgb(112,34,145), rgb(57,52,115)) !important;
}
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(134,93,180) !important;
}

Note:

• fenix_one.css is a combination of the following files:

  • fenix_colors.css
  • fenix_fox.css

[Emma]

Styles & Screenshots:

userContent:

userContent.css (fenix)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

@-moz-document
regexp("^(about:).*") {

    /* Fenix Colors */
    :root {
        --addon-card-background: rgba(171,113,255,0.1) !important;
        --brand-color-accent: rgb(80,54,132) !important;
        --brand-color-accent-active: rgb(80,54,132) !important;
        --brand-color-accent-hover: rgb(80,54,132) !important;
        --color-canvas: rgb(167,111,250) !important;
        --card-outline-color: rgb(171,113,255) !important;
        --card-shadow: var(--shadow-10) !important;
        --card-shadow-hover: var(--card-shadow), 0 0 0 5px var(--card-outline-color) !important;
        --checkbox-border-color: white !important;
        --checkbox-checked-active-bgcolor: var(--in-content-box-background-active) !important;
        --checkbox-checked-bgcolor: var(--in-content-box-border-color) !important;
        --checkbox-checked-border-color: var(--in-content-box-border-color) !important;
        --checkbox-checked-color: var(--in-content-box-text-color) !important;
        --checkbox-checked-hover-bgcolor: var(--in-content-box-background-hover) !important;
        --checkbox-unchecked-active-bgcolor: var(--in-content-box-background-active) !important;
        --checkbox-unchecked-bgcolor: var(--in-content-box-background) !important;
       --checkbox-unchecked-hover-bgcolor: var(--in-content-box-background-hover) !important;
        --dialog-warning-text-color: white !important;
       --in-content-accent-color: rgb(171,113,255) !important;
        --in-content-accent-color-active: rgb(203,158,255) !important;
        --in-content-border-color: rgb(171,113,255) !important;
        --in-content-border-active: rgb(203,158,255) !important;
        --in-content-border-active-shadow: rgb(203,158,255) !important;
        --in-content-border-hover: rgb(203,158,255) !important;
        --in-content-border-invalid: rgb(171,113,255) !important;
        --in-content-box-background: rgb(41,29,79) !important;
        --in-content-box-background-active: rgb(203,158,255) !important;
        --in-content-box-background-hover: rgb(203,158,255) !important;
        --in-content-box-background-odd: var(--in-content-box-info-background) !important;
        --in-content-box-border-color: rgb(171,113,255) !important;
        --in-content-box-text-color: white !important;
        --in-content-box-info-background: rgba(171,113,255,0.2) !important;
        --in-content-button-background: rgb(171,113,255) !important;
        --in-content-button-background-active: rgb(203,158,255) !important;
        --in-content-button-background-hover: rgb(203,158,255) !important;
        --in-content-button-border-color: rgb(171,113,255) !important;
        --in-content-button-border-color-active: rgb(203,158,255) !important;
        --in-content-button-border-color-hover: rgb(203,158,255) !important;
        --in-content-button-text-color: white !important;
        --in-content-button-text-color-active: white !important;
        --in-content-button-text-color-hover: white !important;
        --in-content-category-background: rgb(41,29,79) !important;
        --in-content-category-background-hover: rgb(171,113,255) !important;
        --in-content-category-background-selected: rgb(171,113,255) !important;
        --in-content-category-background-selected-hover: rgb(171,113,255) !important;
        --in-content-category-text: white !important;
        --in-content-category-text-selected: white !important;
        --in-content-danger-button-background: darkred !important;
        --in-content-danger-button-background-active: red !important;
        --in-content-danger-button-background-hover: red !important;
        --in-content-deemphasized-text: lightgray !important;
        --in-content-error-text-color: white !important;
        --in-content-focus-outline-color: rgb(171,113,255) !important;
        --in-content-icon-color: white !important;
        --in-content-item-hover: rgb(203,158,255) !important;
        --in-content-item-hover-text: white !important;
        --in-content-item-selected: rgb(203,158,255) !important;
        --in-content-item-selected-text: white !important;
        --in-content-link-color: rgb(171,113,255) !important;
        --in-content-link-color-active: rgb(203,158,255) !important;
        --in-content-link-color-hover: rgb(203,158,255) !important;
        --in-content-link-color-visited: rgb(171,113,255) !important;
        --in-content-page-background: rgb(41,29,79) !important;
        --in-content-page-color: rgb(171,113,255) !important;
        --in-content-primary-button-background: rgb(171,113,255) !important;
        --in-content-primary-button-background-active: rgb(203,158,255) !important;
        --in-content-primary-button-background-hover: rgb(203,158,255) !important;
        --in-content-primary-button-border-color: rgb(171,113,255) !important;
        --in-content-primary-button-border-hover: rgb(203,158,255) !important;
        --in-content-primary-button-text-color: white !important;
        --in-content-primary-button-text-color-hover: white !important;
        --in-content-selected-text: white !important;
        --in-content-table-background: rgb(41,29,79) !important;
        --in-content-table-border-color: rgb(171,113,255) !important;
        --in-content-table-border-dark-color: rgb(144,89,255) !important;
        --in-content-table-header-background: rgb(41,29,79) !important;
        --in-content-table-header-color: white !important;
        --in-content-text-color: white !important;
        --in-content-warning-container: darkorange !important;
        --shadow-10: 0 1px 4px black !important;
        --shadow-30: 0 4px 16px black !important;
        color: white !important;    
    }
    ::selection {
        background: rgb(171,113,255) !important;
        color: white !important;
    }

    /* About:Addons */
    #categories > .category[selected], #categories > .category.selected {
        background-color: var(--in-content-button-background) !important;
        color: var(--in-content-button-text-color) !important;
    }
    .addon.card {
        background-color: var(--addon-card-background) !important;
    }
    .radio-container-with-text > input {
        border: 2px solid !important;
        background-color: var(--in-content-page-background) !important;
        color: var(--in-content-page-color) !important;
    }
    .radio-container-with-text > input:hover {
        background-color: var(--in-content-button-background-hover) !important;
    }
    .radio-container-with-text > input:active {
        background-color: var(--in-content-button-background-active) !important;
    }

    /* About:Preferences */
    .radio-check {
        border: 2px solid !important;
        border-color: white !important;
        background-color: var(--in-content-page-background) !important;
    }
    .radio-check[selected] {
        border-color: var(--in-content-page-color) !important;
        color: var(--in-content-page-color) !important;
    }
    .web-appearance-choice-image-container {
        background-color: var(--in-content-page-background) !important;
    }
    .web-appearance-choice-image-container:hover {
        background-color: var(--in-content-button-background-hover) !important;
    }
    .web-appearance-choice-image-container:active {
        background-color: var(--in-content-button-background-active) !important;
    }
    .web-appearance-choice input {
        background-color: var(--in-content-page-background) !important;
        border: 2px solid !important;
        border-color: var(--in-content-page-color) !important;
        color: var(--in-content-page-color) !important;
    }
    .web-appearance-choice input:hover {
        background-color: var(--in-content-button-background-hover) !important;
    }
    .web-appearance-choice input:active {
        background-color: var(--in-content-button-background-active) !important;
    }

}

@-moz-document
regexp("^(?!about:).*") {

    /* Apply this customization only on smaller screens in portrait mode */
    @media (orientation: portrait) and (max-width: 720px) {

        /* Table font size (prevents horizontal scroll on some web pages) */
        tr {
            font-size: 13px;
        }

    }

}

@-moz-document
url("about:addons"),
url-prefix("about:addons") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }
        body {
            min-width: 100vw !important;
            max-width:100vw !important;
            width: 100vw !important;
        }

        /* About:Addons */
        .search-label,
        .textbox-search-icons {
            display: none !important;
        }
        input::placeholder {
            color: white !important;
            opacity: 100% !important;
        }
        search-addons > search-textbox {
            background-color: var(--in-content-button-background) !important;
            color: var(--in-content-button-text-color) !important;
            position: fixed !important;
            top: 0 !important;
            left: 0 !important;
            padding: 0 !important;
            width: 49px !important;
        }
        search-addons > search-textbox:hover {
            background-color: var(--in-content-button-background-hover) !important;
        }
        search-addons > search-textbox:active {
            background-color: var(--in-content-button-background-active) !important;
        }
        search-addons > search-textbox[focused] {
            background-color: var(--in-content-page-background) !important;
            border: 2px solid var(--card-outline-color) !important;
            width: 100vw !important;
            z-index: 2 !important;
        }
        .main-search {
            padding-top: 18px !important;
            padding-bottom: 18px !important;
        }
        .main-heading {
            position: fixed !important;
            top: 0 !important;
            padding: 0 !important;
        }
        .page-options-menu {
            position: fixed !important;
            top: 0 !important;
            right: 0 !important;
        }
        #categories > .category {
            margin-left: 0px !important;
        }
        .sidebar-footer-list {
            margin-inline-start: 0 !important;
        }
        .list-section-heading {
            margin-top: 0 !important;
        }
        .addon-description {
            padding-right: 40px !important;
        }
        .addon-badge-recommended {
            margin-right: 10px !important;
        }
        .more-options-button {
            margin-inline-start: -6px !important;
            min-width: 36px !important;
        }
        .toggle-button {
            margin-right: -60px !important;
            margin-bottom: -60px !important;
            height: 12px !important;
            width: 24px !important;
        }
        .toggle-button:before {
            margin-top: -4px !important;
            margin-left: -6px !important;
            height: 18px !important;
            width: 18px !important;
        }

    }

    /* Apply this customization only on smaller screens in portrait mode */
    @media (orientation: portrait) and (max-width: 720px) {

        /* Reduce addon cards width and font to fit display without horizontal scrolling */
        .card {
            max-width: 250px !important;
            font-size: 8pt !important;
        }

    }

}

@-moz-document
url("about:config") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Config */
        #search-container,
        #toolbar,
        #prefs {
            min-width: calc(100vw - 20px) !important;
        }
        #toolbar {
            flex-direction: column;
        }
        #prefs {
            word-wrap: anywhere;
        }
        .checkbox-container {
            margin-top: 6px;
            padding-bottom: 3px;
        }
        tr {
            font-size: 12px;
        }
        th {
            padding-left: 8px !important;
        }

    }

}

@-moz-document
url("about:license") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:License */
        .license-header {
            background-image: none !important;
            padding-inline-end: unset !important;
        }
        #lic-info > pre {
            font-size: 4pt !important;
        }

    }

}

@-moz-document
url("about:policies"),
url-prefix("about:policies") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }

        /* About:Policies */
        #categories > .category {
            margin-left: 0px !important;
        }
        td {
            font-size: 9px;
            padding-left: 5px !important;
            padding-right: 5px !important;
            word-wrap: anywhere;
        }

    }

}

@-moz-document
regexp("about:preferences.*") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }

        /* About:Preferences */
        #searchInput {
            display: none !important;
        }
        .pane-container {
            margin-inline-start: 10px !important;
            margin-inline-end: 10px !important;
            width: calc(100vw - 70px) !important;
            min-width: calc(100vw - 70px) !important;
        }
        #category-general,
        #category-home,
        #category-search,
        #category-privacy,
        #category-more-from-mozilla {
            width: 48px !important;
        }
        #categories > .category {
            margin-left: 0px !important;
        }
        .sidebar-footer-list {
            margin-inline-start: 0 !important;
        }
        label.web-appearance-choice:nth-child(1) > div:nth-child(2) > span:nth-child(2) {
            display: none !important;
        }
        label.web-appearance-choice:nth-child(1) > div:nth-child(2)::after {
            content: "Auto" !important;
        }
        .accessory-button {
            min-width: 100px !important;
        }
        #defaultFont,
        #advancedFonts {
            max-width: 100px !important;
            width: 100px !important;
        }
        #defaultFontSizeLabel {
            margin-left: -196px !important;
        }
        #defaultFontSizeLabel,
        #defaultFontSize {
            margin-bottom: -80px !important;
        }
        #primaryBrowserLocale {
            min-width: 20px !important;
        }

        /* About:Preferences#Privacy */
        #contentBlockingHeader {
            padding-left: 28px !important;
        }
        #trackingProtectionShield {
            margin-inline-end: 0 !important;
            margin-top: -34px !important;
            max-height: 20px !important;
            max-width: 20px !important;
            height: 20px !important;
            width: 20px !important;
        }
        #contentBlockingDescription {
            font-size: 9pt !important;
        }
        #trackingProtectionExceptions {
            padding-left: 0 !important;
            padding-right: 0 !important;
            max-width: 30px !important;
            width: 30px !important;
        }
        #historyMode {
            max-width: 235.5px !important;
            width: 235.5px !important;
        }

        /* About:Preferences#MoreFromMozilla */
        .simple .qr-code-box-title {
          max-width: 235px !important;
          width: 235px !important;
        }

    }

}

@-moz-document
url("about:protections") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Protections */
        #report-content {
            margin: 0 !important;
            padding: 50px !important;
            max-width: 100vw !important;
            width: 100vw !important;
        }
        #mobile-hanger {
            display: none !important;
        }
        .body-wrapper {
            grid-column-start: 1 !important;
            grid-column-end: -1 !important;
        }
        #manage-protections,
        #sign-up-for-monitor-link,
        #save-passwords-button,
        #get-proxy-extension-link {
            grid-area: 2 / 1 / 2 / 6 !important;
        }
        .card-header .wrapper {
            grid-row-gap: 8px !important;
        }
        .card:not(.has-logins) .wrapper div:nth-child(1) {
            grid-column-end: -1 !important;
        }

    }

}

@-moz-document
url("about:rights") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Rights */
        .rights-header {
            background-image: none !important;
            padding-inline-end: unset !important;
        }

    }

}

userContent.css (non-colorized)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

@-moz-document
regexp("^(?!about:).*") {

    /* Apply this customization only on smaller screens in portrait mode */
    @media (orientation: portrait) and (max-width: 720px) {

        /* Table font size (prevents horizontal scroll on some web pages) */
        tr {
            font-size: 13px;
        }

    }

}

@-moz-document
url("about:addons"),
url-prefix("about:addons") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }
        body {
            min-width: 100vw !important;
            max-width:100vw !important;
            width: 100vw !important;
        }

        /* About:Addons */
        .search-label,
        .textbox-search-icons {
            display: none !important;
        }
        input::placeholder {
            color: white !important;
            opacity: 100% !important;
        }
        search-addons > search-textbox {
            background-color: var(--in-content-button-background) !important;
            color: var(--in-content-button-text-color) !important;
            position: fixed !important;
            top: 0 !important;
            left: 0 !important;
            padding: 0 !important;
            width: 49px !important;
        }
        search-addons > search-textbox:hover {
            background-color: var(--in-content-button-background-hover) !important;
        }
        search-addons > search-textbox:active {
            background-color: var(--in-content-button-background-active) !important;
        }
        search-addons > search-textbox[focused] {
            background-color: var(--in-content-page-background) !important;
            border: 2px solid var(--card-outline-color) !important;
            width: 100vw !important;
            z-index: 2 !important;
        }
        .main-search {
            padding-top: 18px !important;
            padding-bottom: 18px !important;
        }
        .main-heading {
            position: fixed !important;
            top: 0 !important;
            padding: 0 !important;
        }
        .page-options-menu {
            position: fixed !important;
            top: 0 !important;
            right: 0 !important;
        }
        #categories > .category {
            margin-left: 0px !important;
        }
        .sidebar-footer-list {
            margin-inline-start: 0 !important;
        }
        .list-section-heading {
            margin-top: 0 !important;
        }
        .addon-description {
            padding-right: 40px !important;
        }
        .addon-badge-recommended {
            margin-right: 10px !important;
        }
        .more-options-button {
            margin-inline-start: -6px !important;
            min-width: 36px !important;
        }
        .toggle-button {
            margin-right: -60px !important;
            margin-bottom: -60px !important;
            height: 12px !important;
            width: 24px !important;
        }
        .toggle-button:before {
            margin-top: -4px !important;
            margin-left: -6px !important;
            height: 18px !important;
            width: 18px !important;
        }

    }

    /* Apply this customization only on smaller screens in portrait mode */
    @media (orientation: portrait) and (max-width: 720px) {

        /* Reduce addon cards width and font to fit display without horizontal scrolling */
        .card {
            max-width: 250px !important;
            font-size: 8pt !important;
        }

    }

}

@-moz-document
url("about:config") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Config */
        #search-container,
        #toolbar,
        #prefs {
            min-width: calc(100vw - 20px) !important;
        }
        #toolbar {
            flex-direction: column;
        }
        #prefs {
            word-wrap: anywhere;
        }
        .checkbox-container {
            margin-top: 6px;
            padding-bottom: 3px;
        }
        tr {
            font-size: 12px;
        }
        th {
            padding-left: 8px !important;
        }

    }

}

@-moz-document
url("about:license") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:License */
        .license-header {
            background-image: none !important;
            padding-inline-end: unset !important;
        }
        #lic-info > pre {
            font-size: 4pt !important;
        }

    }

}

@-moz-document
url("about:policies"),
url-prefix("about:policies") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }

        /* About:Policies */
        #categories > .category {
            margin-left: 0px !important;
        }
        td {
            font-size: 9px;
            padding-left: 5px !important;
            padding-right: 5px !important;
            word-wrap: anywhere;
        }

    }

}

@-moz-document
regexp("about:preferences.*") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* Page width */
        :root {
            --in-content-sidebar-width: 50px !important;
            --sidebar-width: 50px !important;
        }

        /* About:Preferences */
        #searchInput {
            display: none !important;
        }
        .pane-container {
            margin-inline-start: 10px !important;
            margin-inline-end: 10px !important;
            width: calc(100vw - 70px) !important;
            min-width: calc(100vw - 70px) !important;
        }
        #category-general,
        #category-home,
        #category-search,
        #category-privacy,
        #category-more-from-mozilla {
            width: 48px !important;
        }
        #categories > .category {
            margin-left: 0px !important;
        }
        .sidebar-footer-list {
            margin-inline-start: 0 !important;
        }
        label.web-appearance-choice:nth-child(1) > div:nth-child(2) > span:nth-child(2) {
            display: none !important;
        }
        label.web-appearance-choice:nth-child(1) > div:nth-child(2)::after {
            content: "Auto" !important;
        }
        .accessory-button {
            min-width: 100px !important;
        }
        #defaultFont,
        #advancedFonts {
            max-width: 100px !important;
            width: 100px !important;
        }
        #defaultFontSizeLabel {
            margin-left: -196px !important;
        }
        #defaultFontSizeLabel,
        #defaultFontSize {
            margin-bottom: -80px !important;
        }
        #primaryBrowserLocale {
            min-width: 20px !important;
        }

        /* About:Preferences#Privacy */
        #contentBlockingHeader {
            padding-left: 28px !important;
        }
        #trackingProtectionShield {
            margin-inline-end: 0 !important;
            margin-top: -34px !important;
            max-height: 20px !important;
            max-width: 20px !important;
            height: 20px !important;
            width: 20px !important;
        }
        #contentBlockingDescription {
            font-size: 9pt !important;
        }
        #trackingProtectionExceptions {
            padding-left: 0 !important;
            padding-right: 0 !important;
            max-width: 30px !important;
            width: 30px !important;
        }
        #historyMode {
            max-width: 235.5px !important;
            width: 235.5px !important;
        }

        /* About:Preferences#MoreFromMozilla */
        .simple .qr-code-box-title {
          max-width: 235px !important;
          width: 235px !important;
        }

    }

}

@-moz-document
url("about:protections") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Protections */
        #report-content {
            margin: 0 !important;
            padding: 50px !important;
            max-width: 100vw !important;
            width: 100vw !important;
        }
        #mobile-hanger {
            display: none !important;
        }
        .body-wrapper {
            grid-column-start: 1 !important;
            grid-column-end: -1 !important;
        }
        #manage-protections,
        #sign-up-for-monitor-link,
        #save-passwords-button,
        #get-proxy-extension-link {
            grid-area: 2 / 1 / 2 / 6 !important;
        }
        .card-header .wrapper {
            grid-row-gap: 8px !important;
        }
        .card:not(.has-logins) .wrapper div:nth-child(1) {
            grid-column-end: -1 !important;
        }

    }

}

@-moz-document
url("about:rights") {

    /* Apply this customization only on smaller screens */
    @media
    (orientation: landscape) and (max-height: 650px),
    (orientation: portrait) and (max-width: 720px) {

        /* About:Rights */
        .rights-header {
            background-image: none !important;
            padding-inline-end: unset !important;
        }

    }

}

userChrome:

userChrome.css (desktop style)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

/*
@import "fenix_colors.css";
*/
@import "true_mobile_landscape-alt.css";
/*
@import "true_mobile_landscape.css";
*/
@import "appMenu.css";
/*
@import "browser.css";
*/
@import "editBookmarkPanel.css";

@import "findbar.css";

@import "popups.css";

@import "root.css";

@import "tabmenu.css";

@import "urlbar.css";

@import "extensions_menu.css";
/*
@import "alt-browser-alt.css";
*/
@import "custom_rules.css";

@import "hide_tabs_scrollbuttons.css";

@import "tab_close_button_always_on_hover.css";

@import "iconized_main_menu.css";

@import "round_ui_items.css";
/*
@import "tab_counter.css";
*/
@import "hide_tab_manager_menu_button.css";
/*
@import "hide_newtab_+_new-tab_buttons.css";
*/
@import "new-tab-button.css";

@import "tabs_larger_min-width.css";

@import "tabs_fill_available_width.css";
/*
@import "glow.css";

@import "colorful_inactive_tabs.css";

@import "tab_animated_active_border.css";

@import "borderless_transparent_active_tab.css";
*/

userChrome.css (mobile style)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

/*
@import "fenix_colors.css";

@import "true_mobile_landscape-alt.css";
*/
@import "true_mobile_landscape.css";

@import "appMenu.css";

@import "browser.css";

@import "editBookmarkPanel.css";

@import "findbar.css";

@import "popups.css";

@import "root.css";

@import "tabmenu.css";

@import "urlbar.css";

@import "extensions_menu.css";
/*
@import "alt-browser-alt.css";
*/
@import "custom_rules.css";

@import "hide_tabs_scrollbuttons.css";

@import "tab_close_button_always_on_hover.css";

@import "iconized_main_menu.css";

@import "round_ui_items.css";
/*
@import "single_tab_mode-alt.css";

@import "alt-single_tab_mode-alt.css";
*/
@import "single_tab_mode.css";
/*
@import "fenix_theme.css";
*/
@import "numbered_tabs.css";

@import "tab_counter.css";
/*
@import "new-tab-button.css";

@import "glow.css";

@import "colorful_inactive_tabs.css";

@import "tab_animated_active_border.css";

@import "borderless_transparent_active_tab.css";
*/

userChrome.css (true mobile style)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

/*
@import "fenix_colors.css";

@import "true_mobile_landscape-alt.css";
*/
@import "true_mobile_landscape.css";

@import "appMenu.css";
/*
@import "browser.css";
*/
@import "editBookmarkPanel.css";

@import "findbar.css";

@import "popups.css";

@import "root.css";

@import "tabmenu.css";

@import "urlbar.css";

@import "extensions_menu.css";

@import "alt-browser-alt.css";

@import "custom_rules.css";

@import "iconized_main_menu.css";

@import "round_ui_items.css";

@import "tab_counter.css";
/*
@import "true_mobile_mode-alt.css";
*/
@import "true_mobile_mode.css";
/*
@import "dynamic_popups.css";

@import "dynamic_popups_plus.css";

@import "dynamic_popups_max.css";
*/
@import "dynamic_popups_pro.css";
/*
@import "dynamic_popups_pro_max.css";
*/

userChrome.css (fenix)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/


@import "fenix_colors.css";
/*
@import "true_mobile_landscape-alt.css";
*/
@import "true_mobile_landscape.css";

@import "appMenu.css";
/*
@import "browser.css";
*/
@import "editBookmarkPanel.css";

@import "findbar.css";

@import "popups.css";

@import "root.css";

@import "tabmenu.css";

@import "urlbar.css";

@import "extensions_menu.css";

@import "alt-browser-alt.css";

@import "custom_rules.css";
/*
@import "round_ui_items.css";
*/
@import "tab_counter.css";
/*
@import "fenix-alt.css";
*/
@import "fenix.css";
/*
@import "dynamic_popups.css";

@import "dynamic_popups_plus.css";

@import "dynamic_popups_max.css";
*/
@import "dynamic_popups_pro.css";
/*
@import "dynamic_popups_pro_max.css";
*/

userChrome.css (fenix_fox)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

/*
@import "fenix_colors.css";

@import "fenix_fox-alt.css";
*/
@import "fenix_fox.css";
/*
@import "dynamic_popups.css";

@import "dynamic_popups_plus.css";

@import "dynamic_popups_max.css";
*/
@import "dynamic_popups_pro.css";
/*
@import "dynamic_popups_pro_max.css";
*/

userChrome.css (fenix_one)

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source files available here:
   https://gitlab.com/postmarketOS/mobile-config-firefox/-/archive/master/mobile-config-firefox-master.zip
   https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

/*
@import "fenix_one-alt.css";
*/
@import "fenix_one.css";
/*
@import "dynamic_popups.css";

@import "dynamic_popups_plus.css";

@import "dynamic_popups_max.css";
*/
@import "dynamic_popups_pro.css";
/*
@import "dynamic_popups_pro_max.css";
*/

Important:

Reminders

• Remember that you don’t need to save all of the files in this thread; you only need the ones for the styles that you intend to use.

• Remember to disable files that you don’t want by commenting them out in the userChrome.css file.

  • For instance, if you don’t want the toolbars to be moved to the bottom of the screen, then disable the following files by adding slashes and asterisks like this:

/*
@import "browser.css";
*/

/*
@import "alt-browser-alt.css";
*/

• Everything between /* and */ is a comment and will be disabled.

• Remember to enable files that you do want by uncommenting them in the userChrome.css file.

  • For instance, if you want to apply my fenix_colors style, then enable the following file by deleting the slashes and asterisks directly above and below it:

@import "fenix_colors.css";

• Make sure that for each /* that begins a comment, there is a */ that ends the comment.

• If you prefer having a single userChrome file, you can simply rename fenix_fox.css or fenix_one.css to userChrome.css.

  • fenix_one.css includes all code from fenix_colors.css, while fenix_fox.css does not.

  • If you want the Nav Bar at the top of the screen, you can use fenix_fox-alt.css or fenix_one-alt.css instead.

  • You can optionally copy and paste the contents of one of the dynamic_popups files to the bottom of the userChrome.css file.

• Whichever userChrome file or files you decide to use, you will still need a userContent.css file.

• All CSS code must be placed in a folder named chrome which must be placed in your Firefox profile:
  ~/.mozilla/firefox/PROFILE.default-esr/chrome/

Note:

Unified Extensions Menu, Tab Manager Menu, and Main App Menu (≡) can be scrolled with a scrollbar on the right side of the menu popups, and Main App Menu (≡) has a New-Tab button in the menu popup, which makes the New-Tab button in the Tab Bar unnecessary.

Screenshots:

desktop mode

mobile mode

true mobile mode

fenix

fenix_fox

fenix_one (1)

fenix_one (2)

Screenshots showing dynamic_popups:

fenix_one + dynamic_popups (1)

fenix_one + dynamic_popups (2)

fenix_one + dynamic_popups_pro (3)

fenix_one + dynamic_popups_pro (4)

fenix_one + dynamic_popups_pro (5)

fenix_one + dynamic_popups_pro (6)

fenix_one + dynamic_popups_pro_max (1)

fenix_one + dynamic_popups_pro_max (2)

fenix_one + dynamic_popups_pro_max (3)

fenix_one + dynamic_popups_pro_max (4)

Screenshots showing true_mobile_landscape.css and userContent.css (fenix):

fenix_one (1)

fenix_one (2)

fenix_one (3) (old: see note below)

fenix_one (4) (old: see note below)

fenix_one (5) (old: see note below)

fenix_one (6)

fenix_one (7)

fenix_one (8)

fenix_one (9)

fenix_one (10)

fenix_one (about:addons) (1)

fenix_one (about:addons) (2)

fenix_one (about:addons) (3)

fenix_one (about:preferences)

Note:

While the Unified Extensions Menu and other popups are usable in landscape mode, extension popups themselves still suffer from the flickering bug in landscape mode.

I have fixed the extension popups in landscape mode, at the cost of the Tab Manager Menu having some extra blank space to the right and I have fixed the Tab Manager Menu so that it fully expands to fit the popup.

Conclusion:

• This is the final post in the October 2023 Halloween Update multi-post.

• The first post is the October 2023 Halloween Update (post 55).

• For a summary of the updates that were applied to the October 2023 Halloween Update, see the Final Updates (post 70).

• For info about a limitation of the true mobile styles and how to address it, see the Question & Answer (post 85).

• You can follow me on the fediverse:

Overview - user0 - Fedia

[lakei]

@Emma Thanks from me as well for making FF ESR 115 usable again! For me, using the fenix.css profile, the extensions button and the tab count button overlapped on the bottom, but luckily I could easily change that myself. Thanks again!

[Emma]

Thank you for the appreciation!

Yes, the overlapping of those two buttons was a design choice that I made, in order for everything to be arranged as it is on the Firefox for Android app. Rather than using CSS code to move the Unified Extensions Menu button to the left of the URL Bar, I think it makes much more sense to simply have the user move the button themselves in one of a few different ways.

Edit: This overlapping issue has been completely fixed.

[FranklyFlawless]

If you are interested, I have a VPS on OVHcloud I can use for hosting a Forgejo instance, among other public services.

https://forums.puri.sm/t/vps-usage-suggestions/21788 (trust level 1 and up)

The condition is that it is gratis until June 4th, 2025, as that is when the VPS contract ends. If you want it to continue past that, we will need to discuss it further within that thread.

Also, this thread is very slow to load using Firefox ESR on the Librem 5, probably due to all the code. If we relocate all of the code to the Forgejo instance, then you can use this thread as a changelog instead.

[tomoqv]

This thread is so long now that it is difficult to follow the discussion, so excuse me if I post problems that have already been covered.

I have downloaded and copied fenix-one.css and userContent.css to my FF account folder. The issues I am having are:

1. Addon-menu flickers and is not usable on mobile
2. The addon I use the most, “Mobile View Switcher”, which I have placed left most of all my addons is not visible on mobile, just the button in 1)
3. Text on forums.puri.sm (maybe other sites too, but none that I know of) is white on white background, i.e. unreadable

I also have the url bar at the top of the screen and not at the bottom, that was however the same before I upgraded FF and installed the Mobile-Friendly customizations.

Any guidance would be much appreciated.

[tomoqv]

One more thing. I have some difficulty finding the most recent css files. So far I have copied them from this thread.

[Emma]

@FranklyFlawless

If you are interested, I have a VPS on OVHcloud I can use for hosting a Forgejo instance, among other public services.
…
The condition is that it is gratis until June 4th, 2025, as that is when the VPS contract ends.

Sorry, but I am not interested. This forum is a simple place to post my code for others, and I don’t want to complicate things with repos and hosting fees. I made this code for myself and decided to share it here for other Librem 5 users. Everyone is free to share or host this code wherever they want.

I agree with some others that have said this code should be merged into the firefox-esr-mobile-config used by PureOS. @nicole.faerber, I know there is a lot of code (and lots of comments), but it would be nice to know that someone from Purism is at least considering reviewing it so it can be merged into (or outright replace) firefox-esr-mobile-config for Librem 5.

@FranklyFlawless

Also, this thread is very slow to load using Firefox ESR on the Librem 5, probably due to all the code.

It’s actually due to javascript. If you disable javascript in your browser, this thread loads very quickly, just like all the other posts on this and other forums (and most other sites). The only reason you need to enable javascript on this site is to login, but you don’t need to login to view any of my posts as they are all publicly accessible.

@tomoqv

I have downloaded and copied fenix-one.css and userContent.css to my FF account folder.

There are two important things to note:

1. These CSS files must be placed into a folder called chrome. This chrome folder must be placed inside your Firefox profile folder.

2. You must have a file named userContent.css and a file named userChrome.css in the chrome folder.

There are two ways that you can use the fenix_one.css file:

1. Rename the fenix_one.css file to userChrome.css in order to have a single file for all userChrome code.

2. Create a userChrome.css file that imports the fenix_one.css file:

userChrome.css

/* Copyright 2023 user0
 * SPDX-License-Identifier: MPL-2.0 */

/* Source file available here:
   https://forums.puri.sm/t/mobile-friendly-firefox-customizations-for-librem-5/20313
*/

@import "fenix_one.css";

So you either placed these files directly into your Firefox profile folder instead of a chrome folder within your Firefox profile folder, or you didn’t create a userChrome.css file, or you misspelled one or more files (in your comment, you used fenix-one.css instead of fenix_one.css) Either way, PureOS is configured to automatically create a userChrome.css file in your Firefox profile’s chrome folder if one does not exist, but it uses the very basic firefox-esr-mobile-config file, which doesn’t yet contain my code.

So to answer your questions:

@tomoqv

1. Addon-menu flickers and is not usable on mobile

Naming the files correctly and placing them into the correct folders will solve this.

@tomoqv

2. The addon I use the most, “Mobile View Switcher”, which I have placed left most of all my addons is not visible on mobile, just the button in 1)

I originally designed the true_mobile_mode and fenix files assuming that there are no pinned extensions/addons. Your comment has reminded me that this is possible now that extension popups use a dedicated popup instead of relying on the Widget Overflow Menu popup. I have fixed this and will add it soon have updated all true_mobile and fenix files to include it. Check the October 2023 Halloween Update (post 55) for updates.

Note that I have just now updated all true_mobile and fenix files again to properly allow space for the Tab Manager Menu button and pinned toolbar items. The previous method was not good enough. This new one works much better.

This allows for pinned toolbar items (like extensions/addons), while preventing the overlapping issue noted by @tomoqv (thanks for pointing this out so that I could fix it).

@tomoqv

3. Text on forums.puri.sm (maybe other sites too, but none that I know of) is white on white background, i.e. unreadable

I’m not seeing this issue on my end, and you’re not using my code yet (as explained earlier), so I don’t know what is causing this for you.

@tomoqv

I also have the url bar at the top of the screen and not at the bottom, that was however the same before I upgraded FF and installed the Mobile-Friendly customizations.

This is because you are not yet using my Mobile-Friendly customization, as explained earlier.

@tomoqv

One more thing. I have some difficulty finding the most recent css files. So far I have copied them from this thread.

Since I am not hosting this code on any repo or similar, this thread is where all of my code is located. As I explained to the other user, if you disable javascript, this thread loads quickly and is much easier to navigate. Each post is numbered, making it easier to find specific posts.

My most recent update post begins with the October 2023 Halloween Update (post 55), and the final post from that multi-post update is Styles & Screenshots (post 61). All of my most recent code is in the posts from that update (posts 55-61), and there is no need to use code from earlier posts.

[tomoqv]

Thanks for the clear explanation, it works much better now. However, there is some kind of overlap for the buttons still as seen in this screenshot:

I also have two “home” buttons, although the one to the right brings up the addon list.
I am using the firefox-esr system theme and I don’t know if the purple colors come from that one or from the fenix_one.css. I would like a lighter color on toolbar and tabs if possible, how do I change this?
One more thing. I find the popups a bit difficult to use on the mobile, especially scroll between open tabs.

I think I have seen somewhere in this post popups covering the whole screen, but I can’t seem to find that css now.

Thanks for your excellent work on this, very useful!

[Emma]

@tomoqv

I also have two “home” buttons, although the one to the right brings up the addon list.

The one on the left is the real Home button. The one on the right is the Unified Extensions Menu button using the icon of the Home button in order to mimic the Firefox for Android app.

If you don’t like that, you can comment out or remove that section of code from the fenix_one.css file. It exists in two places in the file in order to theme the icon in portrait and landscape modes.

Here is the code responsible for the theming of the icon:

    /* Change Unified Extensions Menu button icon to Home button icon */
    #unified-extensions-button {
        list-style-image: url("chrome://browser/skin/home.svg") !important;
    }

@tomoqv

However, there is some kind of overlap for the buttons still as seen in this screenshot:

You should save the updated version of the fenix_one.css file, which properly allows space for the Tab Manager Menu button and toolbar items while fixing the overlapping issue.

I think you should also consider removing some of the other toolbar buttons. I would recommend removing the Refresh button, and the real Home button (currently on the left of your URL Bar). If you have a use for the Widget Overflow Menu (»), you can put the Home button inside of it, otherwise you can remove them both. And you can tap and hold on a blank area of a page to summon a menu popup that includes buttons for Back, Forward, Refresh, and Add Bookmark.

@tomoqv

I am using the firefox-esr system theme and I don’t know if the purple colors come from that one or from the fenix_one.css. I would like a lighter color on toolbar and tabs if possible, how do I change this?

To disable the colorful toolbar, comment out or remove this section of code from the very bottom of the fenix_one.css file:

/* Private Browsing Mode theme for URL Bar and Nav Bar */
:root {
    --toolbar-field-border-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-border-color: var(--arrowpanel-background) !important;
    --lwt-toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-background-color: var(--arrowpanel-background) !important;
    --toolbar-field-focus-background-color: var(--arrowpanel-background) !important;
}
#nav-bar {
    background-image: -moz-linear-gradient(to right, rgb(112,34,145), rgb(57,52,115)) !important;
}
#navigator-toolbox {
    --lwt-tabs-border-color: rgb(134,93,180) !important;
}

All other colors are managed at the top of the fenix_one.css and userContent.css (fenix) files. If you don’t want to apply any color themes, then you should use fenix_fox.css which is just fenix_one.css without any color themes applied. I haven’t posted a non-colorized userContent.css file yet, but I could do that. I made a userContent.css (non-colorized) file.

Now, when you say you want a lighter color for the tabs, are you talking about the grey bar at the top of your screenshots with the Firefox logo on the left? That looks like the Title Bar to me, which can be disabled using the “Customize Toolbar” feature. Otherwise, what do you mean when you say tabs? The Tab Manager Menu popup? And if so, which part of it?

@tomoqv

One more thing. I find the popups a bit difficult to use on the mobile, especially scroll between open tabs.
…
I think I have seen somewhere in this post popups covering the whole screen, but I can’t seem to find that css now.

What you are looking for is one of my dynamic_popups files, found in True Mobile Modes & Dynamic Popups (post 56). You can see some screenshots of them in Styles & Screenshots (post 61).

For fullscreen popups, you either want dynamic_popups_max.css or dynamic_popups_pro_max.css. They are both fullscreen, but the pro blends the color of the popup container with the popup to make it look truly fullscreen, whereas the other one has a black popup container to show just the rounded popup itself.

Regardless of which dynamic_popups file you use, if any, you should be able to scroll extensions/addons vertically and/or horizontally, depending on the size and shape of the extension/addon popup.

@tomoqv

Thanks for your excellent work on this, very useful!

Thank you for the appreciation and the feedback! It’s nice to see some people trying it out.