Please add support for CSS variables ("custom properties"), a widely supported and crucial feature.

[Hexstream]

Hello,

As can be seen at https://caniuse.com/#feat=css-variables, today CSS variables ("custom properties") is a widely supported feature in all modern standards-compliant browsers. (Of course, Internet Explorer is not in any way modern or standards-compliant.)

I am proudly coding all my sites by hand in raw HTML5/CSS3 according to the W3C standards and recently started using CSS variables heavily (a much-awaited feature!), which results in dozens of validation "errors" whenever someone clicks one of my ✔ CSS3 links in the footer of my pages, which links to the validation results for that page using your validator.

I take pride in having no or very few validation errors in my pages. Having to explain to users that these "errors" are not actual errors and are more akin to a bug in the validator is pretty awkward. So please finally add support for CSS variables, a widely supported and crucial feature.

(edit: I just noticed that the CSS variables specification is "only" at the Candidate Recommendation stage (since 3 december 2015), but still...)

[Hexstream]

Thanks for fixing but the validator instance at https://jigsaw.w3.org/css-validator/ doesn't seem to have been updated yet?... (Example)