- for use with Tree Style Tab
- high space utilization on small displays by reducing the height of the title bar
I like it this way.

To use this:
- Go to
~/Library/Application Support/Firefox/profiles/$your_profile/
- Create a folder called
chrome
- Put the
userChrome.css
in the folde - Open
about:config
in a new tab, and settoolkit.legacyUserProfileCustomizations.stylesheets
totrue
- Customize the toolbar by right-clicking on it
- add a "flexible space" to the very left of the back button.
- this will make room for the macOS windows decorations (close, minimize, expand)
- Restart Firefox to load userChrome.css.