Header issues in Aegaeus

I would like to have a transparent logo and have the rest of the header area be a background color. None of the items I have seen on the forum seem to work on my test site.
Can you please give me directions on how to make this work? The logo is already in place, but I have been unable to change the white background. If this helps, there is some custom css in place that does not seem to be affecting anything, either (it came with the upload). Here is my test site location: http://molehilldesigns.com/test4/