cleverevans on "Centering Twenty Twelve submenu in mobile"

I'm working with a Twenty Twelve Child theme. I made a custom template with a sidebar on the left for the child theme. You can see it in use here: http://curativeprojects.zippysites.com/?page_id=279

However, I'd like to get this menu centered in mobile view. As it is now, here's how it looks:
http://farm4.staticflickr.com/3834/9843158986_0735c484e8.jpg

Any idea of how I can get this centered? Thank you for any and all assistance.