- Place this file in your firefox profile folder, which can be found in your firefox menu:
Help > Troubleshooting Information > Profile Folder
then clickingOpen Folder
. - Place the
userChrome.css
file in thechrome
folder in this directory. If thechrome
folder does not exist, create it. - In Firefox's
about:config
menu toggletoolkit.legacyUserProfileCustomizations.stylesheets
totrue
.
This is designed around the wonderful Tree Style Tab extension.
It would not have been possible without much googling, and the help of the friendly people at /r/FirefoxCSS.
Edit: FF72 broke variable refrencing. (Updated: January, 2020)