bounce.js lets you create tasty CSS3 powered animations in no time.
#css3
CSS Vocabulary
Great resource to make sure you’re calling things by their correct name in CSS-land.
enquire.js
enquire.js is a lightweight, pure JavaScript library for responding to CSS media queries.
Bootstrap
Sleek, intuitive, and powerful mobile first front-end framework for faster and easier web development.
All you need to know about CSS Transitions
All you need to know about CSS Transitions
Nice primer on CSS3 animations from Alex.