Aw it's not problem! And no don't worry, you definitely didn't do anything to mess up the code. I tested it on one of my own (since when I designed the code I tested it on chrome and microsoft edge, but not Firefox oops) and it was the same deal.

Also just wanna let you know I love what you did with it!! It looks so cute. :>

Enjoy using the code!! And yeah if I ever come up with some fix, I'll let you know, though that'll probably be a long while if ever.