The validator complains about conic-gradient. Where is the mistake?

Question

css

.test{
background:conic-gradient(#dadada, #b6b5b5, #d4d0d0, #dad5d5, #cfcccc, 
#e6e6e6, #dddddd, #cfcfcf, #dadada, #b3b2b2, #c7c7c7, #e3e3e3, #d2d2d2,
 #afafaf, #c2c2c2, #bebebe, #c0c0c0, #e5e5e5, #d6d6d6, #c4c4c4, #cacaca, 
 #bdbdbd, #e3e3e3);
}

conclusion:

Answer 1

The validator is a bit late with new features , CSS variables will also swear.

Answer 2

Ignore the validator. It does not have any effect in the final work.