Validating this theme at http://d-theme.com/zen_twilight as CSS 3 produced the following errors.

URI : http://d-theme.com/sites/all/themes/zen_twilight/layout.css?n
287 #header, #content, #navbar, #sidebar-left, #sidebar-right, #footer, #closure-blocks Property word-wrap doesn't exist : break-word
URI : http://d-theme.com/sites/all/themes/zen_twilight/zen_twilight.css?n
288 .node-unpublished div.unpublished, .comment-unpublished div.unpublished Property word-wrap doesn't exist : break-word

Validating this theme as CSS 2.1 produced the same errors plus the following errors.

URI : http://d-theme.com/sites/all/themes/zen_twilight/zen_twilight-fresh.css?n
155 h1.title, h2.title, h3.title, h4.title, h1#site-name, div#site-name, div#site-slogan, #primary a Property text-shadow doesn't exist in CSS level 2.1 but exists in [css2, css3] : 2px 2px 5px black
URI : http://d-theme.com/sites/all/themes/zen_twilight/print.css?n
58 #page Property overflow-y doesn't exist in CSS level 2.1 but exists in [css3] : visible

The XHTML passes the easy W3C validation but fails the Total Validator validation against the W3C schema for XHTML. Name and id attributes must have the same value in the following line. Once this line is fixed, this theme will pass most validation levels.
<a name="top" id="navigation-top">

Comments

Garrett Albright’s picture

Every one of those issues save for the text-shadow one is also going to be present in most other Zen subthemes. You could try posting about this over in Zen's issue queue, but I'll bet they already know.

That being said, I ain't getting rid of the text-shadow, but I'll look into fixing the other issues in the next release. Thanks.