Mobile Menu not Appearing

Hello community!

I am currently using a theme for one of our websites. We've had to edit a good bit of things. I've noticed that our mobile menu icon and menu itself has disappeared. Could someone help me with getting the CSS or html corrected to display the mobile again on smaller devices. I've had help on this menu before from WPDEV and I'm thinking one of those edits made the mobile go away.

Edit: the url is http://cityofhanahan.com

Thanks,
David