Header side margins and padding

First, I want to thank you for making such beautiful themes available for free, and for providing such excellent support for your free products. If my site works out the way I hope, one of my first purchases will be the Pro version of this theme! I was able to adjust the top about bottom margins of the header, but I'd like to get rid of the remaining margin on the left side. Here's a screenshot of what I'm trying to do - the margin/padding I'd like to remove is marked with a red arrow. You can also view the site at www.notjustblack.com. Thanks so much for your help! :)