UPDATE (07.2025): As of Firefox v140 and up, Tweak #1 may no longer be needed as Firefox has updated and changed some widgets. I'll leave it up in the meantime since not everyone is yet on v140.
For additional settings to tweak to get a more pure Gnome Adwaita look, see below: (list updated as of 06.2025)
Firefox Color add-on is limited in what it can change unfortunately, and that is by design for compatibility, so I've created this extra section for settings I've found that allow for an even more pure Gnome Adwaita experience, while still maintaining compatibility with Firefox updates so nothing is ever broken!
Tweak #1: Change the Firefox close "X" button from a giant red icon to an Adwaita friendly icon color set.
- Type about:config in the address bar and press Enter.
- A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
- In the 'Search preference name' panel, type widget.gtk.non-native-titlebar-buttons.enabled
- Click the "toggle button" (two horizontal looking arrows) on the far right side so the preference changes to FALSE. This will change the close button to look like any other GTK app. Toggle back to TRUE if you want to reset to the default value that Firefox provides to undo this change.
- ENJOY!
Tweak #2: Enables rounded corners on the bottom of Firefox window border
- Same steps as above, except on #3 search for: widget.gtk.rounded-bottom-corners
- Set value to TRUE allows rounded corners. Default value is FALSE if you want to revert the change. Changes take effect instantly, no need to restart your browser.
- ENJOY!
