[mort96]

To be fair, dark GTK themes don't really work. I say this as someone who uses dark GTK themes. Far too many applications end up with dark text on a dark background, and Firefox applies your theme colors to websites so websites also end up with dark text on dark backgrounds. At least a dark mode created by the application's authors usually works.

[iforgotpassword]

This has been a problem since forever. Even on Windows 95 it was like that. Probably before that. Windows does have special values for system colors, like text, window background, text background etc. But for some reason, a lot of programs ended up setting the text color explicitly to black and leaving everything else at the system colors. So you better left the color scheme at default. Which is probably fine for the average user, but there were these high contrast schemes which were white on black. People who actually had to rely on this must have had a bad time. Just how these schemes also increased the font size. Doing that, or increasing the system's dpi setting guaranteed that all text in every application would be truncated.

[michaelmrose]

Firefox is a special case of stupid as far as themeing. Fortunately it's possible to both make Firefox's ui dark with css and make Firefox use a light gtk theme for websites with an env variable which is the logical choice.