Image to scroll under header/menu

I’ve made this site from _s and it went very well.

The front page is separate css and I’ve got nothing in the header but the menu. The problem is, I want the menu to be on top of the large photo (section1). So that you can see the image behind the menu.

Making menu transparent or nearly transparent is perfect for the auto scroll to other sections below but I cannot make it transparent over the first image. There’s a space there and I don’t know how to eliminate it. I’ve tried playing with margin-tops and even moved the image into the header which was a disaster, of course.

I’d like it to have this aesthetic: catscarf.com

Can you help? I’m going bonkers 🙂
http://veterinarymarketingsolutions.ca/VMSsite1/