Supersize that Background, Please!
Good use of background cover property and @media queries
CSS selection styles
::selection
Blog | Graphicpeel — iOS Icons Made in Pure CSS
Amazing
Optimiser son application web pour iPhone ou iPod Touch
Good summary of principal tips to start off with
HTML5Rocks - Best Practices for a Faster Web App with HTML5
Google's tips and playground
Announcing an HTML5 mobile app framework for touch devices
check this out
Image Cross Fade Transition with jQuery
Fade one image into another @rem
Webkit CSS Properties
Safari for Desktop and iPhone properties listed in a table. A must have.
gridr buildrrr
Grid builder
CSS Border Radius
Try out border radius and copy/paste css
12 Useful and Free Downloadable Web Design Books
Handy references by Speckyboy Design Magazine
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.
Install multiple versions of IE on your PC | TredoSoft
For use on Windows
LESS - Leaner CSS
LESS extends CSS with variables, mixins, operations and nested rules
24 ways: Working With RGBA Colour
zen-coding
Set of plugins for HTML and CSS hi-speed coding
Transforms
FindMyByIP
What's my IP address and how modern is my browser
Bulletproof @font-face syntax
Paul Irish's take on bullet proofing your @font-face definitions as IE needs an .eot font and the others browsers require .ttf or .otf
XHTML & CSS Lightbox
Look mom, no Javascript
Universal Internet Explorer 6 CSS | For A Beautiful Web
Safari Web Content Guide
Handy reference for developing Web apps that run on Mobile Safari
Conditional-CSS
Conditional-CSS allows you to write maintainable CSS with conditional logic to target specific CSS statements at both individual browsers and groups of browsers.
HTML5 Doctor
Helping you implement HTML 5 today
Proudly Announcing: Modernizr | FarukAt.eş
Modernizr is a small JavaScript toolkit that uses feature detection techniques to determine whether or not the current browser is capable of any of the following features from CSS3 and HTML5.