Browsers do not support color-mix() in relative color syntax

[romainmenke]

I don't see why they do not support this, but this is something users will encounter.

I think this is the most complete supports arg at this time :

@supports (color: lab(from red l a b) {} /* base feature */
@supports (color: lab(from red l 1 1%) {} /* mixed units and percentages */
@supports (color: lab(from red l calc(a + 1) b) {} /* correct value type, must be number, not percentage */
@supports (color: lab(from color-mix(in lab, red, red) l a b) {} /* color-mix() */

@supports (color: lab(from color-mix(in lab, red, red) 1% calc(a + 1) 1%)) {}

[romainmenke]

Going to close this for now.
I don't really like the prospect of producing supports queries like these for any use of relative color syntax.

If this is a significant problem for users we can add special handling for it.