.cube-loader {
  position: relative;
  width: 100px;
  height: 100px;
  transform-style: preserve-3d;
  transform: rotateX(-30deg);
  animation: animate 4s linear infinite;
}

@keyframes animate {
  0% {
    transform: rotateX(-30deg) rotateY(0);
  }

  100% {
    transform: rotateX(-30deg) rotateY(360deg);
  }
}

.cube-loader .cube-wrapper {
  position: absolute;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
}

.cube-loader .cube-wrapper .cube-span {
  position: absolute;
  width: 100%;
  height: 100%;
  transform: rotateY(calc(90deg * var(--i))) translateZ(50px);
  background: linear-gradient(
    to bottom,
    hsl(200, 80%, 50%) 0%,
    hsl(200, 80%, 60%) 100%
  );
}

.cube-top {
  position: absolute;
  width: 100px;
  height: 100px;
  background: hsl(200, 80%, 50%);
  transform: rotateX(90deg) translateZ(50px);
  transform-style: preserve-3d;
}

.cube-top::before {
  content: '';
  position: absolute;
  width: 100px;
  height: 100px;
  background: hsl(200, 80%, 60%);
  transform: translateZ(-100px);
  filter: blur(10px);
  box-shadow: 0 0 10px #333,
              0 0 20px hsl(200, 80%, 60%),
              0 0 30px #333,
              0 0 40px hsl(200, 80%, 60%);
}