EDIT: Is is at least possible to add some sort of tab border? The lack of contrast between tabs was the reason I had disabled Proton.
https://github.com/black7375/Firefox-UI-Fix is a really good set of styles to make proton usable (borders, icons, less padding, etc).
I had to merge it with some of my own customizations. So be aware of that if you already use the Profile chrome directory
I can't distinguish the current tab anymore as well if lighting conditions are less than perfect or if I sit at an angle from the screen.
Or here, same issue, 19 years ago https://bugzilla.mozilla.org/show_bug.cgi?id=173667
(I get that things change, I just thought it was funny)
I also strongly dislike the new tabs as they're totally disconnected from the actual pages they're a tab for with whitespace, less contrast as you mention as well which an issue if you don't have great eyesight. I guess they're willing to lose even more market share over this, which seems pretty silly considering what their trajectory has been...
I've not been bothered by a lot of UI changes as each update has allowed them to be reverted quite easily.
It seems that every update has me swearing for 15 minutes until someone on HN helpfully points to a solution, but not this time. GRR.
I've been a user since the Netscape Communicator days.
Well OK, I'll probably try some userChrome stuff before really switching. But the new tabs are really unusable on my computer.
I use FF developer so I'm a bit ahead of everyone else.
You can fix it with some userChrome.css changes. I'm scared to touch it for fear of fucking my 'tabs on the bottom' css.
You can use policies.json to stop Firefox from nagging you to update Firefox.x