Change the interface of Mozilla Firefox

 Mozilla Firefox is known for its customization options (including themes).  You can also change the buttons in the top of your browser.  To do this, follow these steps:
•  Open Mozilla Firefox
•  Right click on a button or menu bar,
•  In the shortcut menu, click Customize.

 When the window appears, you can move and add buttons with your mouse.  You can also change the display (icon or text), and create a new bar.  Finally, remember that you can revert to the default by clicking the Settings button by default.