This extension finally available here allowed me to switch to Firefox, as it's my vital to-go way to eliminate all awful white backgrounds.

Very happy it has been ported!

Interesting

Great!
Works well, user friendly (for everyone) with a good user interface. It's really a good job.
I installed Stylus first because i known it, but when I saw the mass of useless features... I hate this kind thing just complicated for nothing. So I found your extension. I installd it, customized the ChatGTP conversation page to enlarge the left column and now I am an happy dev :)

+1
...
;>