Hello Coderjoy,

Maybe you'd like to take a look at this add-on :

https://addons.mozilla.org/en-US/firefox/addon/tabcolors/

Even though this is not listed as one of your choices, it might be
worth a try .....

Thank you McCoy. I found that tabcolors theme and tried it. It is fun to play with. There is no mistake which tab is active!

The problem with the lighter themes for me is that the brightness hurts my eyes after awhile... and I get headaches. Yes my display is dimmed and I go on night mode. No, the irritation is not enuf yet to make me stop web hunting. haha

Everything works fine now, except not being able to see the active tab easily enough. What I need is that dark theme, which highlights just the active tab by making it a lighter gray or even dark blue.

Perhaps what I need is hints to find the right JSON file and find which element controls the active tab's color... then I can change it myself.

Thanks again, McCoy.