body {
  background: url(tweed.png);
}

.loading {
  position: absolute;
  left: 50%;
  top: 150px;
  width: 8em;
  height: 8em;
  margin: -4em 0 0 -4em;
  overflow: hidden;
  background: rgba(0, 0, 0, 0.35);
}

.loading > div {
  position: absolute;
  width: 8em;
  height: 8em;
  animation: alpha 2.25s linear infinite forwards;
  background: rgba(231, 76, 60, 0.75);
}

.loading > div:nth-child(1) {
  top: -50%;
  left: -50%;
}

.loading > div:nth-child(2) {
  top: -50%;
  right: -50%;
}

.loading > div:nth-child(3) {
  bottom: -50%;
  right: -50%;
}

.loading > div:nth-child(4) {
  bottom: -50%;
  left: -50%;
}

@keyframes alpha {
  0% {
    transform: rotate(0);
    background: rgba(231, 76, 60, 0.75);
  }
  25% {
    background: rgba(230, 126, 34, 0.75);
  }
  50% {
    border-radius: 50%;
    background: rgba(142, 68, 173, 0.75);
  }
  75% {
    background: rgba(41, 128, 185, 0.75);
  }
  100% {
    transform: rotate(360deg);
    background: rgba(231, 76, 60, 0.75);
  }
}