This is the userChrome.css that can be used to theme Firfox Quantum 59.0 or later versions to look like chrome
Please refer to UserChrome.css to know more about how can you use this.
In an nutshell
- Type about:profiles in your address bar.
- Open the "Root Directory" folder.
- Open or create a folder called "chrome" in the Root Directory. You might already have that folder with the userChrome.css there. You may want to back up this file. Just rename it to userChrome-BAK.css
- Copy my userChrome.css to this folder.
- Restart Firefox
The tabs are too close to the top edge of the window and therefore ditficult to drag, so you can add a little drag area using the following steps.