I use Firefox on KDE with a dark theme (obsidian coast). Parts of some pages, like this very comment input on HN, specify either text color or background color,

I use Firefox on KDE with a dark theme (obsidian coast). Parts of some pages, like this very comment input on HN, specify either text color or background color, but not the other, and so you get dark text on dark bg or light text on light bg. However, these are relatively rare, and I have little issue with this setup. The KDE integration is also not that bad. I use ArchLinux and never installed any special packages, and while tabs and menus do not look exactly like Qt/KDE apps, the difference is barely noticable. And they are the correct color.