Firefox-WinUI is a custom CSS theme that applies the Windows 11 design language to Firefox. It allows use of mica and acrylic materials, and can extend Firefox with custom tweaks.
Firefox stable release is supported. Beta and Nightly may work, but support is limited.
- Open
about:support - Find
Profile Folderthen click onOpen Folder
- Download the files in this repository and extract the zip file
- Install the
spinner-font.tfffont on your system - Copy the
chromefolder anduser.jsfile into your profile folder
The theme allows use of Mica, which adds a translucent layer to the UI, and Acrylic, which blurs various elements, such as context menus, panels and dialogs.
To do this, open about:config and enable the following keys:
widget.windows.micawidget.windows.mica.popups(Set to 1 or 2)browser.tabs.allow_transparent_browser(⚠️ Extends the Mica backdrop into the new tab page area, but may cause issues in some web pages.)
Create the following boolean keys as required:
uc.winui.aptos- Use the new MS Aptos font (Download and install the font from here first)uc.winui.borderless-bookmarks-bar- Remove the border between the navbar and bookmarks baruc.winui.centered-url- Center aligns the URL in the URL Baruc.winui.centered-url-alt- Center aligns the URL in the URL Bar but moves it back to the left when selecteduc.winui.extra-highlights- Adds more highlights to the active tab and context menuuc.winui.grayer-tabbed- Reduces the saturation of the Mica backdrop in dark modeuc.winui.hide-shortcuts- Hide shortcut hints in menus and panelsuc.winui.more-acrylic- Extends the Acrylic texture into the navbar, bookmarks bar and the selected tabuc.winui.navbar-highlights- Adds a highlight to the top of the navbaruc.winui.pill-urlbar- URL bar corners are fully roundeduc.winui.rounded-corners- Creates a gap with rounded corners between the web content and the browser frameuc.winui.rounded-navbar- Rounds the upper corners of the navbaruc.winui.smaller-toolbar-buttons- Shrinks the toolbar buttons to match other WinUI appsuc.winui.taller-bookmarks- Increase the size of the bookmarks bar to match File Explorer's toolbaruc.winui.taller-urlbar- Increase the height of the URL bar to match the early iterations of Windows 11's search baruc.winui.transparent-urlbar- Makes the URL bar transparentuc.winui.urlbar-extra-separators- Add highlighted separators to either side of URL bar
uc.winui.floating-tabs- Disconnects the tabs from the navbar similar to Edge's deprecated Phoenix redesignuc.winui.extension-tray- Compacts the extension menu into a grid of icons similar to the system tray found on Windows 11uc.winui.immersive-navbar- Adds a margin to either side of the navbar to match the margin created by the rounded corners tweak
uc.winui.mac-back-forward- Changes the back/forward glyphs to the ones seen on MacOS
uc.winui.acrylic-animations- Enables acrylic animationsuc.winui.hide-with-1-tab- Hides the tab bar if only one tab is openuc.winui.js-animations- Enables animations that require external.uc.jsfiles due to CSS limitationsuc.winui.extra-animations- Enables extra and unfinished animationsuc.winui.experiments- Enables experimental and unfinished features
- Sidebery extension can be customized with this theme. Paste the code from
sidebery-WinUI.cssinto Sidebery's internal style editor. - Follow this guide to enable JS animations.
Some settings may require a restart to apply. To ensure all settings are fully enabled, go to about:support and click Clear startup cache....
This theme integrates styling and features from:
- Edge-Frfox by bmFtZQ
- Firefox CSS Hacks by MrOtherGuy
- Firefox UWP Style by Guerra24
- Shimmer by Nuclearcodecat
- WaveFox by QNetITQ
Bug reports, feature requests, and code contributions are always welcome.
