Hello,
You would just need to modify the coding below. I would suggest disabling compression, making the changes then clearing the site cache. You most likely made the correct changes but were looking at a cached copy of the site.
Template.CSS - Line 336
#s5_header_area1 {
background: none repeat scroll 0 0 #ffffff;
padding-bottom: 34px;
padding-top: 34px;
}