CustomCSSforFx

The only way to modify ui is by adding custom CSS code to userChrome.css and userContent.css files inside the browser's profile folder. The only way to modify UI is by adding custom CSS code to userChrome.css and userContent.css files inside the browser's profile folder. Keep in mind that CSS code can not create entirely new items, buttons, or toolbars. It only can modify already present UI items. Keep in mind CSS code can not create entirely new items, buttons, or toolbars. It only can modify already present UI items. Edit userChrome.css and userContent.css with any text editor (Notepad++ recommended on Windows) and enable or disable any feature you like by modifying, removing, or out-commenting available import strings. Open CSS files with a text editor. Look through the code and change values the way you need. Some files contain additional instructions about how to tweak the UI for individual cases.