Creating an elastic/static hybrid layout

So i’ve got this new trendy design and I’ve begun the wireframe experimentation phase.

this design would require having a two column setup, in that the center column being fixed width (700px) and the left column (sidebar) taking up whatever space remains between the left hand side of the browser and the left hand side of the center column.

The center column, ideally, would need to be centered no matter what, and the sidebar is left to take up the remaining space on the left.

I’m having a hard time setting up the basic CSS to achieve this behavior, is it possible to say to a div: “Take up 100% of the width available to you”

Any thoughts or suggestions?