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SassMeister-input-HTML.html

<div class="ground"></div>
<div class="sky">
  <div class="cloud variant-1"></div>
  <div class="cloud variant-2"></div>
  <div class="cloud variant-3"></div>
  <div class="cloud variant-4"></div>
  <div class="cloud variant-5"></div>
</div>
<div class="rainbow-preloader">
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="shadow"></div>
  <div class="shadow"></div>
</div>

SassMeister-input.scss

// ----
// libsass (v3.3.6)
// ----


$rainbow : (
  red : rgba(241,90,90,1),
  yellow : rgba(240,196,25,1),
  green : rgba(78,186,111,1),
  blue : rgba(45,149,191,1),
  purple : rgba(149,91,165,1),
);

$i : 1;
$border-width : 12px;
$dimension : 60px;
$offset : $dimension - $border-width;
$clip : $dimension + ($border-width *2);
$z : length($rainbow);

@each $color, $value in $rainbow {
  .rainbow-preloader .rainbow-stripe:nth-child(#{$i}) {
    animation: rainbow-in-out length($rainbow)+s #{$i / (length($rainbow)*2)}s infinite;
    border-color: $value;
    clip: rect(0, $clip, ($clip / 2), 0);
    height: $dimension;
    left: $offset;
    transform : rotate(180deg);
    top: $offset;
    width: $dimension;
    z-index: $z;

    &:before {
      border:($border-width/4) solid darken($value, 10%);
      content: '';
      display: block;
      height: $dimension - $border-width;
      width: $dimension - ($border-width /2);
    }
  }

  $i: $i + 1;
  $dimension: $dimension + ($border-width * 2);
  $offset: $offset - $border-width;
  $clip: $dimension + ($border-width *2);
  $z: $z - 1;
}

.rainbow-preloader {
  height: $dimension / 2;
  left: 50%;
  margin-left: 0 - $dimension / 2;
  margin-top: 0 - $dimension / 2;
  overflow: hidden;
  position: absolute;
  top: 50%;
  width: $dimension;

  &:before,
  &:after {
    $color: #6b9903;
    background: linear-gradient(45deg, transparent 33.333%, $color 33.333%, $color 66.667%, transparent 66.667%),
    		linear-gradient(-45deg, transparent 33.333%, $color 33.333%, $color 66.667%, transparent 66.667%);
    background-size: 6px 34px;
    bottom:0;
    content: '';
    display: block;
    height: 12px;
    left: 0;
    position: absolute;
    width: length($rainbow) * $border-width + ($border-width/2);
    z-index: length($rainbow) *2;
  }

  &:after {
    left:auto;
    right:0;
  }

  .rainbow-stripe {
    border-width: $border-width;
    border-style: solid;
    border-radius: 100%;
    position: absolute;

    &:before {
      border-radius: 100%;
    }
  }

  .shadow {
    animation: shadow-in-out 5s infinite;
    background: rgba(0, 0, 0, 0.2);
    bottom: -1px;
    box-shadow: 0 0 10px 1px rgba(0, 0, 0, 0.5);
    height: 2px;
    left: 0;
    opacity: 0;
    position: absolute;
    width: 0;

    + .shadow {
      left: 118px;
      animation-delay: 0.5s;
    }
  }
}

body {
  overflow-x: hidden;
}

.sky {
  background: linear-gradient(rgb(133,165,204) 0, rgb(208,228,242) 100%);
  box-shadow: 0 0 20px rgb(208,228,242);
  height: 47%;
  left: 0;
  overflow: hidden;
  position: absolute;
  top: 0;
  width: 100%;

  .cloud {
    background: rgb(235,245,252);
    border-radius: 200px;
    box-shadow: 0 1px 1px rgba(0,0,0,0.1);
    height: 39px;
    margin-right: -102px;
    position: absolute;
    right: 0%;
    width: 102px;

    $j: 0;

    @for $i from 1 to 6 {
      &.variant-#{$i} {
        animation: clouds-in-out 15 +$i+s ($j * 2)+s infinite linear;
        top: random(80) * 1%;
        transform: scale(0.2 * $i);
      }
      $j: $j + 1;
    }

    &:before,
    &:after {
      background: rgb(235,245,252);
      border-radius: 100px;
      content: '';
      height: 45px;
      left: 10px;
      position: absolute;
      transform: rotate(30deg);
      top: -10px;
      width: 60px;
    }

    &:after {
      height: 60px;
      left: auto;
      right: 12px;
      top: -24px;
      width: 60px;
    }

  }

}

.ground {
  background: linear-gradient(rgb(110,158,3) 0, rgb(79,115,2) 100%);
  bottom: 0;
  height: 57%;
  left: 0;
  position: absolute;
  right: 0;
}

@-webkit-keyframes rainbow-in-out {
  0% {transform: rotate(180deg);}
  33% {transform: rotate(360deg);}
  66% {transform: rotate(360deg);}
  100% {transform: rotate(540deg);}
}

@-webkit-keyframes shadow-in-out {
  0% { opacity: 0; width: 0;}
  33% { opacity: 1; width: length($rainbow) * $border-width;}
  66% { opacity: 1; width: length($rainbow) * $border-width;}
  100% { opacity: 0; width: 0;}
}

@-webkit-keyframes clouds-in-out {
  0% {right: 0%;}
  100% {right: 105%;}
}

SassMeister-output.css

.rainbow-preloader .rainbow-stripe:nth-child(1) {
  -webkit-animation: rainbow-in-out 5s 0.1s infinite;
          animation: rainbow-in-out 5s 0.1s infinite;
  border-color: #f15a5a;
  clip: rect(0, 84px, 42px, 0);
  height: 60px;
  left: 48px;
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
  top: 48px;
  width: 60px;
  z-index: 5;
}

.rainbow-preloader .rainbow-stripe:nth-child(1):before {
  border: 3px solid #ed2b2b;
  content: '';
  display: block;
  height: 48px;
  width: 54px;
}

.rainbow-preloader .rainbow-stripe:nth-child(2) {
  -webkit-animation: rainbow-in-out 5s 0.2s infinite;
          animation: rainbow-in-out 5s 0.2s infinite;
  border-color: #f0c419;
  clip: rect(0, 108px, 54px, 0);
  height: 84px;
  left: 36px;
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
  top: 36px;
  width: 84px;
  z-index: 4;
}

.rainbow-preloader .rainbow-stripe:nth-child(2):before {
  border: 3px solid #c9a20d;
  content: '';
  display: block;
  height: 72px;
  width: 78px;
}

.rainbow-preloader .rainbow-stripe:nth-child(3) {
  -webkit-animation: rainbow-in-out 5s 0.3s infinite;
          animation: rainbow-in-out 5s 0.3s infinite;
  border-color: #4eba6f;
  clip: rect(0, 132px, 66px, 0);
  height: 108px;
  left: 24px;
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
  top: 24px;
  width: 108px;
  z-index: 3;
}

.rainbow-preloader .rainbow-stripe:nth-child(3):before {
  border: 3px solid #3c9958;
  content: '';
  display: block;
  height: 96px;
  width: 102px;
}

.rainbow-preloader .rainbow-stripe:nth-child(4) {
  -webkit-animation: rainbow-in-out 5s 0.4s infinite;
          animation: rainbow-in-out 5s 0.4s infinite;
  border-color: #2d95bf;
  clip: rect(0, 156px, 78px, 0);
  height: 132px;
  left: 12px;
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
  top: 12px;
  width: 132px;
  z-index: 2;
}

.rainbow-preloader .rainbow-stripe:nth-child(4):before {
  border: 3px solid #237596;
  content: '';
  display: block;
  height: 120px;
  width: 126px;
}

.rainbow-preloader .rainbow-stripe:nth-child(5) {
  -webkit-animation: rainbow-in-out 5s 0.5s infinite;
          animation: rainbow-in-out 5s 0.5s infinite;
  border-color: #955ba5;
  clip: rect(0, 180px, 90px, 0);
  height: 156px;
  left: 0px;
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
  top: 0px;
  width: 156px;
  z-index: 1;
}

.rainbow-preloader .rainbow-stripe:nth-child(5):before {
  border: 3px solid #774984;
  content: '';
  display: block;
  height: 144px;
  width: 150px;
}

.rainbow-preloader {
  height: 90px;
  left: 50%;
  margin-left: -90px;
  margin-top: -90px;
  overflow: hidden;
  position: absolute;
  top: 50%;
  width: 180px;
}

.rainbow-preloader:before, .rainbow-preloader:after {
  background: -webkit-linear-gradient(45deg, transparent 33.333%, #6b9903 33.333%, #6b9903 66.667%, transparent 66.667%), -webkit-linear-gradient(135deg, transparent 33.333%, #6b9903 33.333%, #6b9903 66.667%, transparent 66.667%);
  background: linear-gradient(45deg, transparent 33.333%, #6b9903 33.333%, #6b9903 66.667%, transparent 66.667%), linear-gradient(-45deg, transparent 33.333%, #6b9903 33.333%, #6b9903 66.667%, transparent 66.667%);
  background-size: 6px 34px;
  bottom: 0;
  content: '';
  display: block;
  height: 12px;
  left: 0;
  position: absolute;
  width: 66px;
  z-index: 10;
}

.rainbow-preloader:after {
  left: auto;
  right: 0;
}

.rainbow-preloader .rainbow-stripe {
  border-width: 12px;
  border-style: solid;
  border-radius: 100%;
  position: absolute;
}

.rainbow-preloader .rainbow-stripe:before {
  border-radius: 100%;
}

.rainbow-preloader .shadow {
  -webkit-animation: shadow-in-out 5s infinite;
          animation: shadow-in-out 5s infinite;
  background: rgba(0, 0, 0, 0.2);
  bottom: -1px;
  box-shadow: 0 0 10px 1px rgba(0, 0, 0, 0.5);
  height: 2px;
  left: 0;
  opacity: 0;
  position: absolute;
  width: 0;
}

.rainbow-preloader .shadow + .shadow {
  left: 118px;
  -webkit-animation-delay: 0.5s;
          animation-delay: 0.5s;
}

body {
  overflow-x: hidden;
}

.sky {
  background: -webkit-linear-gradient(#85a5cc 0, #d0e4f2 100%);
  background: linear-gradient(#85a5cc 0, #d0e4f2 100%);
  box-shadow: 0 0 20px #d0e4f2;
  height: 47%;
  left: 0;
  overflow: hidden;
  position: absolute;
  top: 0;
  width: 100%;
}

.sky .cloud {
  background: #ebf5fc;
  border-radius: 200px;
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.1);
  height: 39px;
  margin-right: -102px;
  position: absolute;
  right: 0%;
  width: 102px;
}

.sky .cloud.variant-1 {
  -webkit-animation: clouds-in-out 16s 0s infinite linear;
          animation: clouds-in-out 16s 0s infinite linear;
  top: 61%;
  -webkit-transform: scale(0.2);
      -ms-transform: scale(0.2);
          transform: scale(0.2);
}

.sky .cloud.variant-2 {
  -webkit-animation: clouds-in-out 17s 2s infinite linear;
          animation: clouds-in-out 17s 2s infinite linear;
  top: 16%;
  -webkit-transform: scale(0.4);
      -ms-transform: scale(0.4);
          transform: scale(0.4);
}

.sky .cloud.variant-3 {
  -webkit-animation: clouds-in-out 18s 4s infinite linear;
          animation: clouds-in-out 18s 4s infinite linear;
  top: 76%;
  -webkit-transform: scale(0.6);
      -ms-transform: scale(0.6);
          transform: scale(0.6);
}

.sky .cloud.variant-4 {
  -webkit-animation: clouds-in-out 19s 6s infinite linear;
          animation: clouds-in-out 19s 6s infinite linear;
  top: 76%;
  -webkit-transform: scale(0.8);
      -ms-transform: scale(0.8);
          transform: scale(0.8);
}

.sky .cloud.variant-5 {
  -webkit-animation: clouds-in-out 20s 8s infinite linear;
          animation: clouds-in-out 20s 8s infinite linear;
  top: 4%;
  -webkit-transform: scale(1);
      -ms-transform: scale(1);
          transform: scale(1);
}

.sky .cloud:before, .sky .cloud:after {
  background: #ebf5fc;
  border-radius: 100px;
  content: '';
  height: 45px;
  left: 10px;
  position: absolute;
  -webkit-transform: rotate(30deg);
      -ms-transform: rotate(30deg);
          transform: rotate(30deg);
  top: -10px;
  width: 60px;
}

.sky .cloud:after {
  height: 60px;
  left: auto;
  right: 12px;
  top: -24px;
  width: 60px;
}

.ground {
  background: -webkit-linear-gradient(#6e9e03 0, #4f7302 100%);
  background: linear-gradient(#6e9e03 0, #4f7302 100%);
  bottom: 0;
  height: 57%;
  left: 0;
  position: absolute;
  right: 0;
}

@-webkit-keyframes rainbow-in-out {
  0% {
    -webkit-transform: rotate(180deg);
            transform: rotate(180deg);
  }
  33% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
  66% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
  100% {
    -webkit-transform: rotate(540deg);
            transform: rotate(540deg);
  }
}

@-webkit-keyframes shadow-in-out {
  0% {
    opacity: 0;
    width: 0;
  }
  33% {
    opacity: 1;
    width: 60px;
  }
  66% {
    opacity: 1;
    width: 60px;
  }
  100% {
    opacity: 0;
    width: 0;
  }
}

@-webkit-keyframes clouds-in-out {
  0% {
    right: 0%;
  }
  100% {
    right: 105%;
  }
}

SassMeister-rendered.html

<div class="ground"></div>
<div class="sky">
  <div class="cloud variant-1"></div>
  <div class="cloud variant-2"></div>
  <div class="cloud variant-3"></div>
  <div class="cloud variant-4"></div>
  <div class="cloud variant-5"></div>
</div>
<div class="rainbow-preloader">
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="rainbow-stripe"></div>
  <div class="shadow"></div>
  <div class="shadow"></div>
</div>