center nav menu

Hello,

I am trying to center the nav menu. After applying margin-right:auto; margin-left:auto; to all the classes and id’s with .menu, #site-navigation, I haven’t managed to accomplish it.

The menu either goes way left (the default theme position), or way right with an extra blank nav div line below.

Any help is greatly appreciated. I will be at it for a bit more, but here is the site in case anyone would generously take a look or knows how to fix it https://biztest.netai.net/

Any help is appreciated, thank you!