Hmm... on my browser it seems to work okay still? I just clicked through several customs' pages which looked all intact. Unless I've missed something. Love the site though, such a staple of Zoids customizing that I hope it lives on either in its current form or in an updated format if needed!
Very glad that this seems to be a random bug and not the site itself! Your site truly is amazing. Maybe try clearing your cache? Or Ctrl+F5 (to refresh the cache on that site specifically?). I'm using Chrome fwiw.