body {
  background-color: #04283f;
}

#snow {
  background: none;
  background-image: url("http://www.wearewebstars.dk/codepen/img/s1.png"), url("http://www.wearewebstars.dk/codepen/img//s2.png"), url("http://www.wearewebstars.dk/codepen/img//s3.png");
  height: 100%;
  left: 0;
  position: absolute;
  top: 0;
  width: 100%;
  z-index: 1;
  -webkit-animation: snow 10s linear infinite;
  -moz-animation: snow 10s linear infinite;
  -ms-animation: snow 10s linear infinite;
  animation: snow 10s linear infinite;
}

@keyframes snow {
  0% {
    background-position: 0px 0px, 0px 0px, 0px 0px;
  }
  100% {
    background-position: 500px 1000px, 200px 400px, -100px 300px;
  }
}
@-moz-keyframes snow {
  0% {
    background-position: 0px 0px, 0px 0px, 0px 0px;
  }
  100% {
    background-position: 400px 1000px, 200px 400px, 100px 300px;
  }
}
@-webkit-keyframes snow {
  0% {
    background-position: 0px 0px, 0px 0px, 0px 0px;
  }
  100% {
    background-position: 500px 1000px, 200px 400px, 100px 300px;
  }
}
@-ms-keyframes snow {
  0% {
    background-position: 0px 0px, 0px 0px, 0px 0px;
  }
  100% {
    background-position: 500px 1000px, 200px 400px, 200px 400px;
  }
}