I mean, come on.
other than changing theme or userChrome any other options?
I mean, come on.
This (vertical tabs) is still an experimental feature that isn't even in Firefox Labs yet. It's not that surprising that all edge cases have been ironed out yet. I mean, come on.
Not how it looks for me:
If yours is on linux, I think that's on the system to provide meaningful colors for these elements.
that's with "System theme - auto"? I know I can use another theme, but this one changes with the system, bright during the day, dark at night.
edit:
marginally better with light theme.
What OS is that on?
Fedora, Plasma, Breeze theme (gets changed from light to dark and vice versa on sunrise/sundown)
Sadly don't know enough about that. I suspect it's a specific theme-color it copies for the background of the tab strip, as that is significantly lighter than it is supposed to be.
A place to discuss the news and latest developments on the open-source browser Firefox