How to Remove Rounded Firefox Tabs

Firefox 157.0 made its tabs round along with a bunch of other UI elements. I thought it was ugly as hell, so I spent time figuring out how to change the tabs back. Here’s how to bring back corners in Firefox tabs and other areas. Removing Rounded Tabs This has been tested on Firefox v159. Type about:config in your browser and press enter. If you see a “Proceed with Caution” screen, click on “Accept the Risk and Continue”. Type toolkit.legacyUserProfileCustomizations.stylesheets into the search field and press enter. In the result that comes up, click on the circle icon on the right side. The false value should change to true. Next, go to about:support, search for “Profile Folder”. You should see the full path to your Firefox profile, usually ending with .default-release. Open that directory. In that folder, create a folder named “chrome”. Then, create a file inside it called “userChrome.css”. Copy and paste this CSS into “userChrome.css”: :root { --tab-border-radius: 4px !important; }…