Alex is a contributor to Chrome Developers
Firefox 48 joins Chrome in shipping a native implementation of the Web Animations API.
Better specification compliance and new features coming in Chrome 50.
CSS Grid Layout is a new CSS3 module that provides new layout primitives that are ideal for web applications.
An implementation of Web Animations 1.0 has landed in Blink powering CSS Animations and Transitions.
Respond to change with Object.observe
You can use calc() anywhere a length or number is used, so you can use it for positioning things, or in rgb() color values as well, so it has lots of great uses in a style sheet.
Chromium recently implemented a new feature from HTML5 - scoped stylesheets, aka <style scoped>.