A Firefox userChrome.css theme that aims to recreate the look and feel of Microsoft Edge.

Screenshot: macOS / Firefox 120 / Tweaks: rounded corners, hide forward button.

1. Go to about:support and click the "Open Folder/Show in Finder" button for the root directory of your browser profile.

2. Download the repository and extract the files.

3. From the repository folder, copy the chrome folder and user.js file into your Firefox profile folder.

4. Close and restart Firefox, if performed correctly, the theme should now be installed.

5. Optionally, listed below are some settings that can be changed using about:config:

   Description	Preference Name	Value
   Use Edge-themed context menu on macOS	widget.macos.native-context-menus	false
   Use light theme in private browsing mode	browser.theme.dark-private-windows	false

   Additional tweaks can also be applied to the theme such as Floating tabs, Rounded browser corners and more. See Tweaks.

Note: Most frequently tested on macOS

Theme	Light	Dark
Default (Windows 11)
Floating Tabs + Rounded Corners (Windows 11)
Hide Tabs Bar + Rounded Corners (macOS)

Certain tweaks can be applied to the theme, to enable them navigate to about:config and create a boolean key for each tweak you want to use and set it to true.

To disable a tweak, set the key to false or delete it.

Emulate the look of the rounded tabs feature available in Edge.

uc.tweak.floating-tabs

Add padding and rounded corners around the browser window, as seen in the newest redesign of Edge.

uc.tweak.rounded-corners

This hides the tabs toolbar and is useful when using vertical tab addons such as Sidebery, Tree Style Tab or Tab Center Reborn.

Note: Only works on Windows or macOS.

uc.tweak.hide-tabs-bar

Optional: Only enable when in fullscreen mode (macOS only).

uc.tweak.hide-tabs-bar.only-when-maximised

Removes the extra space at the top of the window when not maximised.

uc.tweak.disable-drag-space

Adds a custom background image to the new tab page.

• In your chrome folder, add an image with a filename of background-0.(jpg/png).
• Optionally, add a second image named background-1.(jpg/png) this will be selected when the dark theme is enabled.

uc.tweak.newtab-background

Hides the forward button when it is not needed, as seen in Edge.

uc.tweak.hide-forward-button

Hide the Firefox logo + wordmark when on the new tab page.

uc.tweak.hide-newtab-logo

Removes the ability for custom themes to change the colour of the selected tabs, instead forcing them to match the toolbar colour. This can be useful when using themes designed for the Firefox's default Proton style.

(Left: OFF, Right: ON)

uc.tweak.force-tab-colour

Displays the navigation buttons (Back, Forward, Reload, Bookmark) in the right-click menu vertically like all the other menu items.

uc.tweak.vertical-context-navigation

Removes the underlining or highlighting of certain characters in the context menu. These underlines correspond to the key that when pressed, activates the item.

For example, "Undo" becomes "Undo" and "Inspect (Q)" becomes "Inspect".

uc.tweak.context-menu.hide-access-key

Removes the vertical separating lines between the tabs, resulting in a cleaner look.

uc.tweak.remove-tab-separators

When the tabs become too small, Firefox will hide the close buttons for non-active tabs to save space. This tweak will always display the close buttons when hovering over a tab.

uc.tweak.show-tab-close-button-on-hover

This reverts the custom font-size set on the context menu, only applies to Windows users.

uc.tweak.smaller-context-menu-text

Disable the custom Edge-themed context menu and use the default Firefox menus.

uc.tweak.revert-context-menu

Mica is broken due to changes made in the Firefox 115 update, Mica has now been removed from this theme.

If you still have uc.tweak.win11-mica set in about:config you can safely delete it.

muckSponge - MaterialFox

Microsoft - Fluent UI System Icons

KibSquib48 - MicaFox