A community maintained repository of userChrome.css tweaks for Firefox

  • By Tim Van den Eynde
  • Last update: Jan 5, 2023
  • Comments: 16

A community maintained repository of userChrome.css tweaks for Firefox

Every file should only contain a single, specific tweak. No full themes or anything. Users of this repository should be able to easily combine the different tweaks into a setup of their liking.

Incompatibilities between different files can happen. There's not much we can do about it. Just keep this in mind.

The master branch should always track Nightly. When a version merges into beta, a new branch is created for this specific Firefox version. If any code is broken on this branch, it is possible to cherry-pick the necessary commits without pulling other broken code in.

If you wish to contribute to this repository, please read CONTRIBUTING.md.




  • 1

    Move the hamburger menu to the top left

    This moves the hamburger menu to the top left, to the left of the first tab, in the handy blank space that's available there if the window isn't maximised. If it is maximised, then that blank space is inserted anyway so there's room for the menu button. This is more or less where the original Firefox menu button went, as opposed to the Chrome standard of having it as a toolbar button at the right.

    Only tested on Windows 7 - if others want to test (and tweak if necessary) for other OS'es, that would be cool.

  • 2

    Navbar auto hide update for 58+ compatibility, and add Bookmark bar support

    58+ removes the --tab-toolbar-navbar-overlap variable, so some re-jigging is required.

    I've also fixed an issue where the spacers on the nav bar wouldn't count as hover-able areas, and added support for hiding the bookmark bar too (if that is visible). I'm not sure if that should be a separate file or not, I suppose it's possible you would want to auto-hide only one or the other, but to me it made more sense that they would both hide or show together.

  • 3

    Merge tabbar and navbar (Linux)

    I reviewed the code and modified it a bit, it looks quite good on my end but YMMV.

    Compact: https://www.pictshare.net/pbu075lbk5.png Normal: https://www.pictshare.net/p4snhmwtm3.png

  • 4

    Create vertical-context-navigation.css

    Modifies context menu to place context-navigation buttons vertically. Not the cleanest code and might not work with all extensions or OS. Only Win10 tested. Also, hoping I'm doing this right.. Haven't really used github before

  • 5

    Create auto-hide-sidebar.css

    Auto-hide sidebar.

    • #sidebar-box specifies the cursor distance from the edge for the sidebar to become visible. (default: 10px)
    • #sidebar-box:hover specifies the sidebar's width when visible. (default: 200px)
    • If the sidebar is right-aligned replace "left" with "right", and "margin-right" with "margin-left"
    • Mind that "margin-right" is negatiive.
    • #sidebar-header is always hidden, remove line 41 to restore it.
    • The divider between the sidebar and the rest of the browser can be customized with #sidebar-splitter.
  • 6

    Reload button inside addressbar, on the left

    A shameless fork of pull request #47, because this cannot sensibly be done with an extension (only if I moved the whole pageaction group to the left), at least not yet.

  • 7

    Sliding bookmarks

    I did not make this, however the original source is linked on the file so i hope it's ok.

    Also, i wasn't entirely sure where to put this so i put it under toolbars/. If that's the wrong directory just tell me.

  • 8

    My styles

    Here is a list of my styles that should work in Firefox 57, please add them to this repository. Maybe you can get the original screenshots with some hacking around, or just make new ones.

    https://userstyles.org/styles/146846/android-style-tabs-fx-57 - androidStyleTabs.css

    https://userstyles.org/styles/121537/compact-find-bar-fx-50 - compactFindBar.css

    https://userstyles.org/styles/140689/gray-flat-tab-icons-fx - flatTabIcons.css

    https://userstyles.org/styles/92774/hide-back-forward-in-maximized-window-fx-42 - hideBackForward.css

    https://userstyles.org/styles/146845/merge-tabs-and-navigation-bar-fx-57 - mergeTabsNavigation.css

    https://userstyles.org/styles/121010/move-identity-box-to-the-right-fx-50 -identityBoxRight.css

    https://userstyles.org/styles/146843/prevent-tab-overflow-fx - preventTabOverflow.css

    https://userstyles.org/styles/141315/private-browsing-address-bar-background - privateAddressBackground.css

  • 9

    Emphasize "Not Secure"

    Uses a hidden about:config setting.

    Also, sorry about the commit mess, I forgot not to push to upstream right away and slightly messed up later. (3917e013aed002792690d41ad99747827a6030a8 7d48ebbb3b8e8dd02e737527a284951fc8000b42 13337c6bc965e7e6ab241a50f2e40e0a99a64efd)

  • 10

    Fix move-identity-lock-right.css for Photon

    Fixed the style to look right on latest Nightly, also added inline comments to code. You can keep the original in a separate branch (FX 56) I guess, but I won't help maintain it as I only want my Photon-supported styles here.

  • 11

    Bookmarks displayed on toolbars appear as favicons

    With this CSS, bookmarks displayed on a toolbar appear as favicons. Text is hidden as per screenshot.

    This is a Classic Theme Restorer feature, or so I hear.

  • 12

    Request for tabs vertically on left or right side.

    At my workstation I find if comfortable to have the tabs arraigned vertically on the left. This allows for better vertical space, especially with wide and ultrawide displays. Is this possible to do with css tweaks?

  • 13

    remove-padding-when-not-maximized-macOS-Windows.css doesn't work

    Title. This userChrome snippet is not working.


    For reference, I'm using Mozilla Firefox v86 (32-bit).

  • 14

    sliding-bookmarks-bar.css doesn't seem to work correctly on its own

    Title. This userChrome snippet is not working correctly.

    It displays a weird black bar on the place where the bookmarks toolbar is originally located.


    For reference, I'm using Mozilla Firefox v86 (32-bit).

  • 15

    osx FF78 change bookmarks manager window font size


    need help modifying userChrome.css so that I could read the bookmarks (losing my eyesight ;-{, and tons of bookmarks being used) .. have tried most anything I could find discussed, but none of it works .. (the zoom about:config setting is NOT what I need, as that changes the tab-font-size too, and I'd like that to stay as is, same for menus)

    any help would be appreciated


  • 16

    "multi-row-tabs-rounded-corners.css" on "77.0.1" does not work properly.

    multi-row-tabs-rounded-corners.css on 77.0.1 does not work properly:

    1. All non-active tabs are displayed but hidden
    2. All tabs are still displayed in single row
    3. Firefox opening becomes slow enough