.sky-amination {
  height: 100vh;
  background-color: #007ced;
  background: linear-gradient(to bottom, #007ced 1%, #cce7ff 100%);
}

.sky-amination .clouds {
  position: relative;
  height: 100%;
  background: url(https://static.radulescu.me/examples/clouds/clouds1000.png);
  background: url(https://static.radulescu.me/examples/clouds/clouds1000.png) 0
      200px,
    url(https://static.radulescu.me/examples/clouds/clouds1200_1.png) 0 300px,
    url(https://static.radulescu.me/examples/clouds/clouds1000_blur3.png) 100px
      250px;
  animation: wind 20s linear infinite;
}

@keyframes wind {
  0% {
    background-position: 0 200px, 0 300px, 100px 250px;
  }
  100% {
    background-position: 1000px 200px, 1200px 300px, 1100px 250px;
  }
}