Background of header.

Hi, I am building a new site and this is the url: http://www.ccc-cologne.com/ I just cant get rid of the green colour at the top (part of the header). If i put a header the green colour still remains like a frame. All that I want is to replace this with the same colour as the backgroung colour (#1e73be) or get rid of the whole header space... Could someone help me do this.   Santhosh