Libraries

• SASS - CSS extension language which allows variables, mixins and rules nesting.

Resources

Guides

• SMACSS - Scalable and Modular Architecture for CSS. Learn how to structure your CSS to allow for flexibility and maintainability as your project and your team grows.
• BEM - Blocks, Elements and Modifiers. A clear system to name elements.
• CSS Property Index - All properties in an easy-to-digest form.