Questions re mobile site problems

Hi I've got a test site up with the Full Frame Pro Theme at http://www-test.shelfdig.com/ We love the theme! It seems to be working fine on a desktop, but on my iPhone 5, there is one main issue: The nav bar goes to 2 lines only in mobile (http://www-test.shelfdig.com/wp-content/uploads/2015/03/photo-1.png). This happens with your full frame demo even so I don't think the bug is just on our end (screenshot at http://www-test.shelfdig.com/wp-content/uploads/2015/03/photo.png) Any advice how to make that stay on a single line? ... also not a bug, but I'm curious if you have a quick way in the custom css to adjust the width that the menu bar condenses at. If so, I would appreciate that too. Thanks! Michele