CSS Validation

Perhaps you could provide a link to a site where it does not validate?

Sure. Here it is: https://www.emaxy.it/

This is what I get on the validator: https://validator.w3.org/check?uri=http%3A%2F%2Fwww.emaxy.it%2F&charset=%28detect+automatically%29&doctype=Inline&group=0.

The document located at <https://www.emaxy.it/&gt; was successfully checked as XHTML 1.0 Transitional. This means that the resource in question identified itself as “XHTML 1.0 Transitional” and that we successfully performed a formal validation of it. The parser implementations we used for this check are based on OpenSP (SGML/XML) and libxml2 (XML).

Try it in a browser where you are not logged in.

Hi Ron,
I’m talking about CSS validation, not XHTML validation.
If you try with the CSS validator located at https://jigsaw.w3.org/css-validator/ the result is this and you can see that the file genesis-responsive-slider/style.css?ver=0.9.2 raises some errors.
Thank you.

Some of the CSS is for IE8 & earlier. ex

filter: alpha(opacity=80);

I understand that some styles are for IE, but I think that CSS validation is probably more important than full IE8 support (at least on sites that should obey accessibility rules).
I would suggest to put all IE styles in a separate CSS file and include it within conditional comments (here’s a tutorial about the recommended way to do this) or have a plugin option to include/exclude the additional IE styles.
I’m available to help you with this if you need. Thanks for your attention.