UPDATE:
It was the browser’s fault.
I restarted everything and in the end it had nothing to do with WordPress.
All is well again!
Thanks for trying to help, Michelle 🙂
Thanks for responding, Michelle.
All other websites look fine on this browser (Safari). I tried to do Command+0, but nothing happened.
I tried logging out of my admin account for the site thinking maybe that was causing the wonky changes – but that didn’t do anything either.
