Cards sometimes fail on IOS/Safari devices

[Stevec4]

I was having an issue using the flash cards in safari on an IOS device. After several card flips they would stop working.
By adding overflow: hidden to .card class if solved the issue.
.card { -webkit-perspective: 1600; perspective: 1600; color: #222; display: none; font-family: SchoolBell; font-size: 30px; height: 300px; line-height: 60px; position: relative; width: 500px; overflow: hidden; }