Mobile Menu hides behind content; but only on external host

Hey all,

I’m helping my parents with a website, and the mobile version of the site has a hamburger menu that slides out. It displays fine on Webflow, but once I export it over to their current host, it hides behind the content. I’ve played with Z-index with no luck, and I’m new to all this so I can’t think of any other solution. Does anyone know what might be happening?

My read only is here:

And this is the current live version:

Thank you!