
I finally decided to update Firefox to the latest after seeing that developers have finally ported over some of the useful extensions that I need.
The default layout of Quantum leaves a lot to be desired especially because it does not allow customization. The squared tabs and the URL bar's position is not as I like it.
If you will like to bring back the classic look the older Firefox browser then add my code to your userChrome.css which is located in the profile/chrome/ of your Firefox folder.
This code will put tabs at the bottom and make them rounded. It will also add a clear border so it looks like the screenshot.