Also, I use a custom userChrome.css that uses as basis https://github.com/aris-t2/customcssforfx
From time to time comes a Firefox update that makes mandatory to update such userChrome.css and waste time trying to find what additionally changed and needs to be updated by my_userChrome.css also, but as reward for such pain I have the same view that was used to be with the browsers years ago. I mean, from top to down with small gray icons: menu bar, url bar with addons at the right, bookmarks bar where I put folders based by category (unfold and fold on press), and finally tabs and pinned tabs over the page content.
With the minimalist tendency of current browsers, they sacrifice what makes a browser usable, an usability killing that also forces the user to continually waste time making hacks for to conserve it. But at least it can be done, so at my side I just pray that it at least stays that way.
This repo (and that subreddit) has all the info on setting stuff up in Firefox: https://github.com/aris-t2/customcssforfx and even has a CSS example for doing multi-tab lines: https://github.com/Aris-t2/CustomCSSforFx/blob/master/curren...
Here's something to use if the UI makes you really upset.
Also you will probably miss translation: https://addons.mozilla.org/en-US/firefox/addon/traduzir-pagi...
- https://github.com/black7375/Firefox-UI-Fix - a good base including different light/dark themes. See Tips for code to put tabs on bottom
- https://github.com/aris-t2/customcssforfx - huge collection of different CSS that you can mix together for the perfectly customised UI
Hoping some day someone builds a playground so it's easy to build/customise interfaces through a GUI as I find it a bit of a chore to get things tweaked exactly right!
In the meantime it's worth noting you can use remote debugging[1] to live edit the interface.
1. https://www.reddit.com/r/FirefoxCSS/comments/73dvty/tutorial...