I’m searching for a CSS framework that is responsive, large (more than 1000px), and where I can do the folowing :
Large design :

Normal design :

Mobile design :

Any suggestions ? I have tried 960.gs, Titan framework, 1140 css grid, and the Golden Grid System, but I’m not sure I can do everything I want in any of them.
You want to serve different css by detecting the screen size.
This tool does it: Adapt.js (Take a look at Less too)
With Adapt.js you can do stuff like this: