entry-title background goes 'behind' header-image?

I want to have the ‘entry-title’ in a white box partially obscuring the ‘header-image’. I’ve got the text more or less where I want it but while the text appears ‘above’ the image, it’s background color does not. It’s as if the header-image is between the text and the background color in the title. Any suggestions welcome! The site I’m working on is just a demo and I’ve only made minor changes to the CSS so it can all be scrapped if it’s horribly wrong. The demo site is here.

Thanks!