A quick color course and how it will be implemented as a device independent feature in CSS4.
WeasyPrint is a visual rendering engine for HTML and CSS that can export to PDF. It aims to support web standards for printing.
When those Wordpress (or else) theme CSS files take time to update in the browser. This should maybe be added to all themes.
The Atom Shell framework lets you write cross-platform desktop applications using JavaScript, HTML and CSS.
It is based on node.js and Chromium and is used in the Atom editor.
Opera mobile displays numbers as links thinking it's phone numbers. Not really pleasant. Here's a code hint to remove this "feature".