Autofocus Theme: Change Menu Background Color

Pertains to: matthewwendeln.com

As is my links in my menu on the top right have a square black background, which is no good. I’d like to make that text background transparent, but for the life of me I can’t find where or how to do this. Is this not a simple addition of a ‘background: transparent;’ in my css? Here’s what the code for the menu currently looks like:

[CSS moderated as per the Forum Rules. Please just post a link to your site.]

Any help would be much appreciated!

(Autofocus lets you change the background of text wholesale, but I’d like to keep black as it is and just change the background of the menu links)