Isn’t #2 the only option?
Websites specifying color for foreground (or background) and assuming browsers will use whatever color they’re expecting for the other has always existed, and still exists
If you’re getting fancy and specifying colors, you can’t cheap out and not specify all colors
If the browser ignores all your colors at that point, then it’s displaying as the user intended
If you only specified some of the colors, it’s a bug of the website
git was created because a proprietary VCS was being a dick