> For config (assuming you mean prefs in about:config)

And userChrome/Content.css... looks like I’ll need to dropbox those.

Editing css was essential to make the switch from Vivaldi to FF - yesterday! Getting TreestyleTab et al. to feel like Vivaldi with vertical tabs required some fiddling: sidebar without menu, hidden top tabs, darker text color, etc.

In any case, it’s my new daily driver and I'm quite satisfied so far. Even set DDG as the default while at it.