I’ve edited the tabs and overall colour theme. There are some other css added for specific websites in my sqlite. The sqlite file just needs to be copied over to your firefox profile directory. For me it is located at $HOME/.mozilla/firefox/<profilename>/
Just make sure you backup your existing stylish.sqlite file or if you haven’t installed stylish yet, go download it here.
Edit: Oops forgot to provide the link to my stylish.sqlite which can be found on my github.