Is it possible to get stacked divs to fit whole width of screen?

[charlyanderson]

So I am building a site using the 1140px grid system.

My main content goes 3col 6col 3col making 12 cols and they stack when scaling down the window size.

My question is, is it possible to get them to fill the screen once scaled down? Currently the 6col sits nicely but the 3cols only take up half the screen.

I get the whole principle of cols but wondering if I can adapt it someway to get the desire effect.

[charlyanderson]

If anyone is interested, I resolved this. Turns out I had got align:left in my css for the sidebar and navigation. This was already defined by the 1140 grid system css so once I took my extra css out it worked just fine