vulcan/public/css/preloader.css

/*http://codepen.io/Michiel/pen/ogXrBX*/
header [role="progressbar"][aria-busy="true"] {
  position: fixed;
  bottom: 0;
  left: 0;
  padding-top: 4px;
  width: 100%;
  z-index: 999;
  background-color: #159756;
  -webkit-animation: preloader-background linear 3.5s infinite;
          animation: preloader-background linear 3.5s infinite;
}
header [role="progressbar"][aria-busy="true"]::before, header [role="progressbar"][aria-busy="true"]::after {
  display: block;
  position: absolute;
  top: 0;
  z-index: 2;
  width: 0;
  height: 4px;
  background: #afa;
  -webkit-animation: preloader-front linear 3.5s infinite;
          animation: preloader-front linear 3.5s infinite;
  content: '';
}
header [role="progressbar"][aria-busy="true"]::before {
  right: 50%;
}
header [role="progressbar"][aria-busy="true"]::after {
  left: 50%;
}

@-webkit-keyframes preloader-background {
  0%, 24.9% {
    background-color: #159756;
  }
  25%, 49.9% {
    background-color: #da4733;
  }
  50%, 74.9% {
    background-color: #3b78e7;
  }
  75%, 100% {
    background-color: #fdba2c;
  }
}

@keyframes preloader-background {
  0%, 24.9% {
    background-color: #159756;
  }
  25%, 49.9% {
    background-color: #da4733;
  }
  50%, 74.9% {
    background-color: #3b78e7;
  }
  75%, 100% {
    background-color: #fdba2c;
  }
}
@-webkit-keyframes preloader-front {
  0% {
    width: 0;
    background-color: #da4733;
  }
  24.9% {
    width: 50%;
    background-color: #da4733;
  }
  25% {
    width: 0;
    background-color: #3b78e7;
  }
  49.9% {
    width: 50%;
    background-color: #3b78e7;
  }
  50% {
    width: 0;
    background-color: #fdba2c;
  }
  74.9% {
    width: 50%;
    background-color: #fdba2c;
  }
  75% {
    width: 0%;
    background-color: #159756;
  }
  100% {
    width: 50%;
    background-color: #159756;
  }
}
@keyframes preloader-front {
  0% {
    width: 0;
    background-color: #da4733;
  }
  24.9% {
    width: 50%;
    background-color: #da4733;
  }
  25% {
    width: 0;
    background-color: #3b78e7;
  }
  49.9% {
    width: 50%;
    background-color: #3b78e7;
  }
  50% {
    width: 0;
    background-color: #fdba2c;
  }
  74.9% {
    width: 50%;
    background-color: #fdba2c;
  }
  75% {
    width: 0%;
    background-color: #159756;
  }
  100% {
    width: 50%;
    background-color: #159756;
  }
}