Ok, I couldn’t figure it out, so I ended up just rewriting the whole page and deactivating the old page.
I still can’t figure out what was wrong, and I still have the old page saved. I can’t even open it up as a preview.
It’s also weird that the menu bar at the top of the screen shows blank as well (but still a black strip).
How is it possible that only one of my pages could be non-functional, and then when I remake it, the new, identical page is just fine?