WTF, HTML and CSS?
Common WordPress Development Mistakes and How to Fix Them
WordPress Coding Standards
Modular Grid Pattern
Useful web app to generate a grid pattern
ProCSSor - Advanced CSS Prettifier
CSS beautifier
Image Cross Fade Transition with jQuery
Fade one image into another @rem
gridr buildrrr
Grid builder
CSS3 Please! The Cross-Browser CSS3 Rule Generator
You can edit the underlined values in this css file but don't worry about making sure the corresponding values match, that's all done automagically for you.
zen-coding
Set of plugins for HTML and CSS hi-speed coding
Transforms