feat(color): suport color space syntax

[fuchunhui]

new feature for color-syntax

For easy reference in other specifications, opaque black is defined as the color rgb(0 0 0 / 100%); transparent black is the same color, but fully transparent—i.e. rgb(0 0 0 / 0%).
All of the syntactic forms defined in this specification use space, not comma, to separate the color components. They also use a solidus ("/") to separate an optional alpha term from the color components.

example:

rgb(254 134 22)
rgb(254 134 22 / 20%)
rgba(154 234 222 / 20%)
hsl(120 75% 50%)
hsl(120 75% 50% / 0.25)
hsla(120.0 75% 50% / 25%)