html, body {
  margin: 0;
  padding:0;
  height: 100%
}

.sky {
  height: 400px;
  width: 2000px;
  background: linear-gradient(to top, rgba(0,127,213,0), rgba(163,217,255,1));
  background-repeat:repeat-x;
  position: relative;
  overflow: hidden;
  -webkit-animation: sky_background 200s ease-out infinite;
  -moz-animation: sky_background 200s ease-out infinite;
  -o-animation: sky_background 200s ease-out infinite;
  animation: sky_background 200s ease-out infinite;
  -webkit-transform: translate3d(0, 0, 0);
  -ms-transform: translate3d(0, 0, 0);
  -o-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
}

.sky .clouds_one {
  background: url("../images/cloud_one.png");
  background-repeat: repeat-x;
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 300%;
  -webkit-animation: cloud_one 200s linear infinite;
  -moz-animation: cloud_one 200s linear infinite;
  -o-animation: cloud_one 200s linear infinite;
  animation: cloud_one 200s linear infinite;
  -webkit-transform: translate3d(0, 0, 0);
  -ms-transform: translate3d(0, 0, 0);
  -o-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
}

.sky .clouds_two {
  background: url("../images/cloud_two.png");
  background-repeat: repeat-x;
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 300%;
  -webkit-animation: cloud_two 300s linear infinite;
  -moz-animation: cloud_two 300s linear infinite;
  -o-animation: cloud_two 300s linear infinite;
  animation: cloud_two 300s linear infinite;
  -webkit-transform: translate3d(0, 0, 0);
  -ms-transform: translate3d(0, 0, 0);
  -o-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
}

.sky .clouds_three {
  background: url("../images/cloud_three.png");
  background-repeat: repeat-x;
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 300%;
  -webkit-animation: cloud_three 400s linear infinite;
  -moz-animation: cloud_three 400s linear infinite;
  -o-animation: cloud_three 400s linear infinite;
  animation: cloud_three 400s linear infinite;
  -webkit-transform: translate3d(0, 0, 0);
  -ms-transform: translate3d(0, 0, 0);
  -o-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
}

@-webkit-keyframes sky_background {
 	background: linear-gradient(#007fd5, #a3d9ff);
}
@-moz-keyframes sky_background {
 	background: linear-gradient(#007fd5, #a3d9ff);
}
@keyframes sky_background {
 	background: linear-gradient(#007fd5, #a3d9ff);
}

@-webkit-keyframes cloud_one {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@-moz-keyframes cloud_one {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@keyframes cloud_one {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}

@-webkit-keyframes cloud_two {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@-moz-keyframes cloud_two {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@keyframes cloud_two {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}

@-webkit-keyframes cloud_three {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@-moz-keyframes cloud_three {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}
@keyframes cloud_three {
  0% {
	left: 0
  }
  100% {
	left: -200%
  }
}