I am not one to do extensive tweaking to my machine, but this is important to me, so I spent an hour experimenting. And I have to say, I am pretty satisfied. Even though it isn't straightforward, Firefox actually can look nice and uncluttered.
If you're like me and want both privacy and aesthetics, here are some pointers:
- Switch to the light theme.
- Hide everything you can in the address/nav bar by clicking through the UI. Some settings are obscure, but you can get rid of a lot.
- Hide even more using userChrome.css [0], including the outdated blue bar at the top of an active tab.
My userChrome.css looks like this and works like a charm: https://gist.github.com/iamdamian/9efc271208bfb5ca52dc51572b...Now we just need Mozilla to come up with a more modern-looking logo.