Harmonic Theme – center the navigation menu

Hi,
I would really appreciate help about how to center the menu in Harmonic theme. I did search the forum and tried many suggested margin related and text related solutions but I cannot find the block that moves the menu to the center.

The theme is simple and clear, which I love but the design of my page requires menu at the center.

Their demo is at https://harmonicdemo.wordpress.com

Thank you in advance!