I’ve tested it on iOS 12, iOS 11, and Android Nougat on different mobile phones and browsers (Chrome, Safari, and Firefox), and via Chrome, Firefox, and Safari on macOS. In each instance, the same issue arises: The minimized main menu (again, only on the front page of the site) won’t activate when clicked. The standard menu on any desktop browser works just fine; the minimized menu works on literally every other page except the front page.