How to make Header Image Same as Background Image?

This is my first post, so I apologize if I inadvertently violate a forum rule.

I want to model the top of my site, which is here, after this website.Specifically, I want the textured blue background in my site to fill all the white space above the red nav bar.

I can’t tell whether the model site has inserted the logo into the background, or has somehow made the header background match the site’s background. Using firebug, it looks like the latter, but I’m not really sure. And if that’s the case, how do I do that?

Suggestions? Thanks.