<!DOCTYPE html>
<html>
<head>
<style>
body {
-webkit-animation-name: throb;
-webkit-animation-iteration-count: infinite;
-webkit-animation-duration: 2s;
-webkit-animation-timing-function: ease-in-out;
}
@-webkit-keyframes throb {
0% { background-color: #fff; }
50% { background-color: #000; }
100% { background-color: #fff; }
}
</style>
</head>
<body>
</body>
</html>