let themes control select and option colors

[wjackson]

This is a fix for #2369.

[ada-x64]

Tested this on my Manjaro Linux machine, can confirm that the changes fix the bug. LGTM! cc @texodus

[texodus]

Thanks for the PR @wjackson!

Adding new CSS variables for these properties requires this variable to be specified for all themes, as you've noticed. As there is not compelling reason to style option background in isolation, this shouldn't be public (or at the very least, should default to the themes' palette).

I can't test this as its a Windows bug (not a Chrome bug as the Issue says), but I've added this default in #2422 anyway, closing

[wjackson]

there is not compelling reason to style option background in isolation

Yeah that makes sense.

I can't test this as its a Windows bug (not a Chrome bug as the Issue says), but I've added this default in #2422

The screenshots in #2369 came from Chrome on Linux so it's not a Windows bug. As mentioned in the issue, I tested for and found the bug on a couple different Linuxes and Windows.

I tested your fix (upgrade-emsdk:017b3d301) on Linux where I originally found the bug and it works. Thanks!