Twitter Bootstrap

“Sleek, intuitive, and powerful front-end framework for faster and easier web development.”

Gumby 960 Grid Responsive CSS Framework

“Gumby Framework was built to be the most maleable grid framework you’ve ever used while still maintaining the familiarity and ease-of-use of the grid you’ve always used.”

Variable Grid System – Generate CSS grid templates based on ‘960 Grid System’

“The variable grid system is a quick way to generate an underlying CSS grid for your site. The CSS generated file is based on the 960 Grid System.”

What’s the Deal With Display: Inline-Block?

“We’ve been using floats for layout pretty much since we left tables behind. It’s a quirky solution that can often cause troubles, but if you know what you’re doing, it works. One interesting alternative to floats that people are turning to more and more lately is to set the display value of an element to ...

CSS tests and experiments

http://www.brunildo.org/test/index.html

Best practices for modern web development

Learn How to Develop the Next Generation of Applications for the Web => https://github.com/google/WebFundamentals

CSS contents and browser compatibility

http://www.quirksmode.org/css/contents.html

Initializr – With Great Templates Comes Great Responsivity!

http://verekia.com/initializr/responsive-template

CSS Image Replacement Museum

http://css-tricks.com/examples/ImageReplacement/

CSS Media Queries & Using Available Space

http://css-tricks.com/css-media-queries/