[css-color-adjust-1] Disallow repetition of color-scheme keywords? #3848
Description
Currently 'color-scheme' is defined to allow repeated keywords, like color-scheme: light light, and the repetitions are just dropped from the computed value.
I copied this from Rune's initial spec, but I'm not sure if we want it; we don't usually allow meaningful things to be repeated. Would it be okay to just call this invalid?