Rp Tutorials

I am using this layout. Does anyone know how to widen the body of the layout? The entry boxes and the navigation division? I feel like such a dumbass, but I've tried everything and have yet to figure out where it works correctly.

I'm adding a header, which has seemingly worked fine. I had to add a simple body { margin-top: in order to position the layout where I need in order to make all of the entries and navigation visible, but no matter what I do...it seems I can't get the width and alignment to match. Anyone got any ideas?