Transparent Menu

Hello, I am trying to figure out how make the header menu transparent with the main image behind it. I have figured out how to make the menu background transparent but the menu will not show the main image under it. It seems that the two areas wont overlap. I took away the transparency so you can view it as is. I would like the transparent menu to look similar to heading at http://stockfresh.com/.

http://limess.flywheelsites.com/?page_id=4
To see the site use:
login : flywheel
password: daily-sweater

Thank You