If you’re writing CSS, you should learn what PostCSS is, what it really does, and what it can be used for.
The flexbox specification contains properties that enable us to modify markup in new ways. Drew Minns explains how to use quantity ordering with pure CSS.
Articles & Tutorials
An in-depth article Sara Soueidan on how to style the contents of the SVG <use> element and overcome some challenges it brings.
Chris Coyier discusses the advantages and disadvantages of different approaches to print stylesheets.
Miguel Palhas shares a couple of good CSS animation tips & tricks while explaining how his 3D animated atom experiment works.
Craig Hockenberry on using system font in the new version of OS X (new -apple-system font family).
The most challenging part of performance optimization, writes Lara Hogan, is getting other people to care about it.
Modern CSS linter. Supports the latest CSS syntax and features, including custom properties, range media features and calc().
A really nice collection of loading indicators animated with CSS.