Since Firefox uses GTK to implement it’s Linux desktop interface, it’s already integrated with the generic GNOME look and feel. GNOME3 applications use a slightly different look, though. They also have a particular behavior when maximizing: the title bar dissapear (this happens for example with Nautilus or Web).
Now that you want to improve your Firefox experience with GNOME, you can do it by:
- Install GNOME3 Firefox Theme. It will modify the Firefox theme by modifying tabs (they will look exactly the same that the ones on Web or Nautilus) and the main toolbar buttons.
- Install HTitle extension. It will remove the top bar when maximizing the Firefox window. There is a GNOME Shell extension that already does something similar, but the final result is not the same.
After you install these 2 extensions, you’ll get this.
Firefox fully integrated with GNOME Shell
Ain’t it cool? Remember to hide the Menu bar in order to have only the “Firefox” button.