Navigation menu moves to both sides of Logo on very large screens

We're modifying our site and have switched to the Pacific template. We are experiencing some very strange behaviour on our site:

If the viewer is looking at the site using a very large 4k monitor or if someone zooms their browser window way out (see screenshots attached) the navigation menu items split and move up to either side of the logo. Does anyone know of any CSS code that can be added to force the nav bar to stay below the logo on all pages?

Thanks, Mike
https://www.slte.org

@tuanphan Thank you VERY MUCH! That little snippet worked perfectly!