trying to create a background with css with no luck

[Nikita22]

I am trying to create a website background similar to http://www.latlong.net/ but i'm not having any luck. Is this green and gray background one image or is that a green image at the top with a gray background?I cannot find the css for the background to see what they have, it comes out all jumbled with alot of extra google maps css on it.Can anyone see what they are doing to do the strip across the top and gray below?Thanks!