Prevent Navigation Stacking

Hello! Ideally, I want to prevent the centered navigation from stacking into two lines. I've tried a few different coding options, but most either: a) don't stay centered b) start overlapping the elements instead when making the browser smaller c) run the navigation off the page and make a scrollbar.

I would like the navigation to stay centered and just move using the space available, and then go hamburger early instead of overlapping.

Thanks!

Can you share site url?