সিএসএস animation-duration

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
.animation {
  width: 50px;
  height: 50px;
  background: pink;
  position: relative;
  animation: mymove infinite;
  animation-duration: 3s;
}

@keyframes mymove {
  from {top: 0px;}
  to {top: 200px;}
}
</style>
</head>
<body>
<div class="animation"></div>
</body>
</html>