<div class="progress"></div>

<div class="cube-wrap">
  <div class="cube">
    <div class="side top"></div>
    <div class="side bottom"></div>
    <div class="side front"></div>
    <div class="side back"></div>
    <div class="side left"></div>
    <div class="side right"></div>
  </div>
</div>

body {
  padding: 0;
  margin: 0;
  min-height: 500vh;
  background-color: rgb(139, 201, 228);
  animation: body 1s linear;
}
@keyframes body {
  0% {
    background-color: rgb(139, 201, 228);
    color: rgb(139, 201, 228);
  }
  100% {
    background-color: rgb(19, 48, 97);
    color: rgb(19, 48, 97);
  }
}

::-webkit-scrollbar {
  background: currentcolor;
  width: 10px;
}
::-webkit-scrollbar-track {
  background: currentcolor;
}
::-webkit-scrollbar-thumb {
  background: #fff;
  border-radius: 10px;
}

.progress {
  height: 3px;
  width: 0%;
  background-color: #fff;
  position: fixed;
  top: 0;
  left: 0;
  animation: progress 1s linear;
}
@keyframes progress {
  0% {
    background-color: #fff;
    width: 0%;
  }
  100% {
    background-color: rgb(20, 255, 226);
    width: 100%;
  }
}

.cube-wrap {
  --size: 30vmin;
  position: fixed;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  perspective: 100vmin;
}
.cube {
  transform-style: preserve-3d;
  transform: rotateX(0deg) rotateZ(45deg) rotateY(-45deg);
  animation: cube 1s linear;
}
@keyframes cube {
  0% {
    transform: rotateX(0deg) rotateZ(45deg) rotateY(-45deg);
  }
  100% {
    transform: rotateX(360deg) rotateZ(45deg) rotateY(-45deg);
  }
}

.side {
  position: absolute;
  width: var(--size);
  height: var(--size);
  background-color: #eee;
  backface-visibility: visible;
  top: calc(var(--size) * -.5);
  left: calc(var(--size) * -.5);
}
.top {
  background-color: #fff;
  transform: rotateX(90deg) translateZ(calc(var(--size) * .5));
}
.bottom {
  background-color: #999;
  transform: rotateX(90deg) translateZ(calc(var(--size) * -.5));
}
.left {
  background-color: #ccc;
  transform: rotateY(90deg) translateZ(calc(var(--size) * .5));
}
.right {
  background-color: #ddd;
  transform: rotateY(90deg) translateZ(calc(var(--size) * -.5));
}
.front {
  background-color: #aaa;
  transform: translateZ(calc(var(--size) * .5));
}
.back {
  background-color: #bbb;
  transform: translateZ(calc(var(--size) * -.5));
}

:root * {
  /* Pause the animation */
  animation-play-state: paused;
  /* Bind the animation to scroll */
  animation-delay: calc(var(--scroll) * -1s);
  /* These last 2 properites clean up overshoot weirdness */
  animation-iteration-count: 1;
  animation-fill-mode: both;
}

var offsetStart = 0;
var offsetEnd = 0;

window.addEventListener('scroll', () => {
  document.documentElement.style.setProperty('--scroll', ( window.pageYOffset - offsetStart ) / ( document.body.offsetHeight - offsetStart - offsetEnd - window.innerHeight ));
}, false);