תבנית:ענן

<style> div#cloud {

 position: absolute;
 top: 0px;
 width: 250px;
 height: 200px;
 background: -webkit-linear-gradient(#ffffff, #808080);
 background: -o-linear-gradient(#ffffff, #808080);
 background: -moz-linear-gradient(#ffffff, #808080);
 background: linear-gradient(#ffffff, #808080);
 border-radius: 100%;
 opacity: 0;
 filter: blur(20px);
 -webkit-filter: blur(20px);

} div#cloud::before, div#cloud::after {

 position: relative;
 width: 150px;
 height: 100px;
 content: " ";
 display: block;
 left: -80px;
 top: 100px;
 border-radius: 100%;
 background: -webkit-linear-gradient(#ffffff, #808080);
 background: -o-linear-gradient(#ffffff, #808080);
 background: -moz-linear-gradient(#ffffff, #808080);
 background: linear-gradient(#ffffff, #808080);

} div#cloud::after {

 left: 200px;
 height: 80px;
 top: -50px;

} div#cloud:nth-child(1) {

 animation: moving 31s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 31s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 175px;
 top: 20px;

} div#cloud:nth-child(2) {

 animation: moving 25s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 25s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 100px;
 top: 20px;

} div#cloud:nth-child(3) {

 animation: moving 28s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 28s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 150px;
 top: 130px;

} div#cloud:nth-child(4) {

 animation: moving 20s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 20s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 200px;
 top: 100px;

} div#cloud:nth-child(5) {

 animation: moving 27s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 27s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 125px;
 top: 50px;

} div#cloud:nth-child(6) {

 animation: moving 22s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 22s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 150px;
 top: 50px;

} div#cloud:nth-child(7) {

 animation: moving 28s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 28s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 225px;
 top: 75px;

} div#cloud:nth-child(8) {

 animation: moving 30s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 30s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 505px;
 top: 60px;

} div#cloud:nth-child(9) {

 animation: moving 25s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 25s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 375px;
 top: 140px;

} div#cloud:nth-child(10) {

 animation: moving 23s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 23s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 525px;
 top: 70px;

} div#cloud:nth-child(11) {

 animation: moving 22s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 22s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 375px;
 top: 50px;

} div#cloud:nth-child(12) {

 animation: moving 25s;
 animation-iteration-coint: infinite;
 animation-timing-function: linear;
 -webkit-animation: moving 25s;
 -webkit-animation-iteration-count: infinite;
 -webkit-animation-timing-function: linear;
 left: 275px;
 top: 60px;

} @-webkit-keyframes moving {

 0% {
   margin-left: 0%;
   opacity: 0;
 }
 10% {
   opacity: 1;
 }
 100% {
   margin-left: 100%;
 }

} @keyframes moving {

 0% {
   margin-left: 0%;
   opacity: 0;
 }
 10% {
   opacity: 1;
 }
 100% {
   margin-left: 100%;
 }

} </style>