Here is my portal page for CSS.
- I use Twitter Bootstrap, rather than write CSS from scratch and/or copy-n-paste CSS from different resources. It is very efficient web UI toolkit and provides more than CSS.
- Customize themes. After a while, you may get tired of the default theme, you can customize themes at either the official website (not interactive) or interactive website like Bootstrap ThemeRoller. Or, you can simply well-designed themes from website like Bootswatch (free but few themes) and WrapBootstrap (paid but more themes).
- CDN. BootstrapCDN provides CDN for Bootstrap and Bootswatch themes.
- Alternatives. I haven’t used other alternatives (e.g. Flat UI Kit), since I don’t have a good reason to switch.
- What is CSS preprocessors? Intro to Sass and LESS.
- Sass and LESS comparison (side-by-side comparison, and a bonus article)
- W3Schools: property, selector, unit, browser support, aural style sheet
- [Book] CSS: The missing manual
- [Book] CSS: the Definitive Guide
- Experiences with Bootstrap, Compass, Sass, and LESS (stack overflow post)