CSS Animation not firing on device

Can't seem to get this simple CSS animation to fire on IOS.
Anyone see anything wrong with this?

Can I not run css animations in WebViewUI?

.bounce {
  -webkit-animation-duration: 1s;
  -webkit-animation-fill-mode: both;
  -webkit-animation-timing-function: ease-in-out;
  -webkit-animation-iteration-count: 1;
  -webkit-animation-name: bounce;
}

@-webkit-keyframes bounce {
  0%, 20%, 50%, 80%, 100% {
    -webkit-transform: translateY(0);
  }
  40% {
    -webkit-transform: translateY(-10px);
  }
  60% {
    -webkit-transform: translateY(-5px);
  }
}