Menu borders are super wonky/dotted lines

The site is https://bedlamtheatre.org/

I’m having trouble figuring out what’s going on with my menu bar & the borders around each menu heading or subheading. When you click through to any of the links, like to “About” or to the “Menu” or “Hours,” the selected page is turning up with dotted line borders. If you click through to “Bedlamites,” same thing, but on the black background. How do I make this go away? I can’t see anywhere in my code that is making dotted lines happen.

Any help would be much appreciated. I’m fairly new at WordPress/coding, but I’ll try my best to keep uP!