<ul>
  <li></li>
  <li></li>
  <li></li>
  <li></li>
</ul>
:root {
  --radius: 100px;
  --scale: 1;
  --deg: 0deg;
  --dur: 4;
  --repeat: infinite;
}

body {
  margin:4em 2em 1em 2em;
  background: rgb(30, 30, 30);
}

li {
  --hue:270;
  width: var(--radius);
  height: var(--radius);
  background: hsl(var(--hue), 80%, 60%);
  border-radius: 5%;
  
   animation: thing calc(var(--dur) * 1s) linear var(--repeat) alternate;
}

li:nth-of-type(1) {
  --scale:.8;
  --deg:67deg; 
}

li:nth-of-type(2) {
  --scale:.9;
  --deg:-30deg;
}

li:nth-of-type(3) {
  --scale:1.2;
  --deg:50deg;
}

li:nth-of-type(4) {
  --scale:1.4;
  --deg:-80deg;
}

@keyframes thing {
 100% {transform: scale(calc(var(--scale) * 1)) rotate(var(--deg));}
}  



ul {
  display:flex;
  flex-direction: row;
  justify-content: space-around;
   width: 100%;
}
var boxes = document.querySelectorAll('li');

var hDiff = 100;
var hStart = 210;

// random numbers and magic numbers to pick random-ish hues for the box colours
boxes.forEach(function(li) {
   li.style.setProperty('--hue', Math.floor(Math.random() * hDiff * 2) + hStart);
});


// var boxes = Array.from(document.querySelectorAll('li'));
Rerun