How do I center header nav buttons?

[Noosphere]

My template has nav buttons located at the top of the header. As a result of a recent customization, they ended up going from being centered on the template to aligned at the far left (screen shot).

I've tried every possible centering code I know to fix it, but nothing works so clearly I'm missing something. I've attached a copy of the header template code (stripped of any centering code efforts of my own) to give a clean view. If someone could instruct me on how to properly insert the code that needs to be replaced to center the nav buttons again, it would be greatly appreciated.

Thanks in advance for any assistance.