Try this:
HTML Code:
#header {
margin-top: 5em;
}
#toplinks {
top: -5em !important;
right: 0 !important;
width: 100%;
background: linear-gradient(to bottom, #33cc33 0%,#003300 100%);
}
And of course edit the gradient to your liking. I only included the W3C compliant code...I use this site to generate gradient CSS for multi-browser support:
http://www.colorzilla.com/gradient-editor/