Black by MaDonna
Nice and Simple
Just black. But with the new update to FF 44, something got broken and open tabs, nav bar and bookmarks bar are grey. I solved it by installing the Classic Theme Restorer addon. It worked like a charm. Just open addons, click on CTR options. Go to Toolbars (3) and under Toolbars, check Navigation Toolbar: Remove Backgroung Color. Then, under Bookmarks Toolbar, check Remove Background Color and you're done. You can tweak other things in there while you're at it.
Thanks MaDonna for your time and work on this theme. I hope the kinks get sorted out. :)
I do not have a Persona Plus addon. I did try removing Black then reinstalling, but same problem: grey, not black.
simple, lo que andaba buscando, mozilla deberia incluir estos temas solidos directo en el navegador.