Fluid Grids by Ethan Marcotte

Resources

When it comes to responsive web design, fluid grids are the foundation.

Quick overview
To design responsively, you need fluid images, media queries to suss out the breakpoints, and a fluid grid to contain them all. Ethan Marcotte explains that with a wee bit of math, you can create fluid grids that put content first, elegantly, regardless of the size of the viewport.