I think the Blackboard theme is the best looking (just a personal preference, of course), but the active tab seems to be designed to stand out against the black background by turning black. I could just change themes, but that changes everything I like, too. I'd just like to slightly tweak this one, change a line in some file to something like "active-tab-color: #F00BAA", and get back to work, but I can't figure out where to put that line or what its exact format would be.
I finally found the Blackboard theme definition conveniently XML-formatted then packed into a pseudo-directory that was actually a zip-compressed file buried a couple of levels deep in the hidden pseudo-directory of the Mac app itself. I suppose that should have been obvious, but the problem is that the theme definition doesn't seem to define the tab color, so I'm either misreading it or something else is defining it. According to Google, the appearance of tabs in ST2 was at least partly defined by .png files located with the theme definitions, allowing users to set a tab color preference using nothing more than PhotoShop, but those seem to have been taken away and hidden in a place that isn't nearly so obvious, perhaps encrypted and hidden in a printer driver or a hollow tree.
Do you masters of the Sublime Way know where to look and the magic words needed to change a tab color in ST3? Or the tab text color? Or if tab colors require PhotoShop, the hollow tree where the .pngs are stashed?