Support css variables in style designer

[lofcz]

Persisted component, background color is set to some css variable. Works fine:

When input is edited and result is a valid usage of var() style manager incorrectly treats it as a invalid value:

[artf]

Yeah right now all the input values are processed by an internal validator, so for many types something like var(* is not a valid value.
Probably I'll need to find a way to extend that kind of behavior.

[lofcz]

It might be worth to allow for a custom handler to override the default impl. For example I could then write just --my-var and transform that to var(--my-var). But variables with valid notation should probably be supported by default.

[artf]

But variables with valid notation should probably be supported by default.

Yeah, I agree.

[lexoyo]

Hello
I'm thinking we should have a plugin to support css variables or design tokens
Would you agree ? Will that be in the core @artf ?