README.md

September 20, 2026 · View on GitHub

Preview

Installation

  1. Move the theme files into your profile's chrome folder.
  2. Configure about:config with these preferences:
PreferenceValuePlatform / Notes
toolkit.legacyUserProfileCustomizations.stylesheetstrueRequired
svg.context-properties.content.enabledtrueRequired
browser.newtabpage.activity-stream.nova.enabledfalseRequired
browser.nova.enabledfalseRequired
widget.windows.micatrueWindows¹
widget.windows.mica.toplevel-backdrop2Windows
widget.gtk.rounded-bottom-corners.enabledtrueLinux
widget.macos.native-context-menusfalsemacOS

¹ Windows: Requires enabling "System theme — auto" in Firefox Add-ons manager.

Important

Required for East Asian (CJK) input: Enable "Address Bar: show results during IME composition" in Settings > Firefox Labs.

  1. Restart Firefox to apply changes.

Customization

Create these preferences in about:config to modify the UI:

Boolean Toggles

PreferenceDescriptionNotes
gwfox.urlbarMove address bar to sidebarNot for hover-expand mode
gwfox.toolbarAuto-hide bookmarks toolbar
gwfox.urlbar.acAuto-collapse address barFor horizontal tabs
gwfox.blurAdd acrylic effect to floating panel
gwfox.acEnable accent colorEdit --bg0 in CSS to customize
gwfox.atbcAdaptive Tab Bar Colour compatibility
gwfox.newtabEnable New Tab transparencyRequires allow_transparent_browser
gwfox.noborderRemove window borders
gwfox.bmsEnable main window transparencyLinux
gwfox.iconsAdd menu icons
gwfox.mwcEnable macOS-style window controlsWindows/Linux
gwfox.mscEnable macOS-style tab close button
gwfox.twcEnable theme-styled window controlsWindows/Linux
gwfox.twc.acAuto-collapse window controls
gwfox.fxaReplace app menu icon with avatarRequires sign-in
gwfox.fsiEnable FluentUI System Icons

Note

  • When gwfox.urlbar is enabled, the collapsed sidebar expands in an Arc-like hover mode, which you can trigger from the left.
  • For gwfox.urlbar.ac: If you want it to trigger only when the window size is reduced, you can manually modify userChrome.css.
Click to expand steps

Search for the following line in your userChrome.css:

@media -moz-pref("gwfox.urlbar.ac") and (not -moz-pref("sidebar.verticalTabs")) {

And change it to:

@media -moz-pref("gwfox.urlbar.ac") and (not -moz-pref("sidebar.verticalTabs")) and (width < 1500px) {

Feel free to adjust 1500px to any value that fits your needs.

Numerical Setting

PreferenceDescriptionValues
gwfox.sidebarSet sidebar width1 (narrow), 3 (wide), or otherwise (default)