FAQ Accordion using vanilla JS

Generally, I felt my code was sloppy and could be written better, especially my JS. But right now, I need to concentrate on making it work first, and then I can worry about DRY and semantics. I'd really appreciate help in making the accordions respond to each other. When one is open, all others should close. I couldn't do that yet. I had a lot of help with the assignment, but they aren't on here, so I can't tag them. Thanks for your help in advance.