@function randomNum($max, $min: 0, $u: 1) {

  @return ($min + random($max)) * $u;

}

​

@function randomConicGradient() {

  $n: 16 + random(16);

  $list: ();

  @for $i from 0 to $n {

    $list: $list, rgba(hsl(100, randomNum(250, 5, 10%), randomNum(1, 1, 1%)), randomNum(100, 0, .01));

  }

  @return conic-gradient($list, nth($list, 1));

}

​

body {

    overflow: hidden;

}

​

div {

    width: 100vw;

    height: 100vh;

  margin: 0;

  background: 

    radial-gradient(hsl(9, randomNum(100, 75, 1%), randomNum(100, 75%, 1%)), black);

  &:before, &:after {

    position: absolute;

    top: 50%; left: 50%;

    margin: -100vmax; 

    width: 200vmax; 

        height: 200vmax;

    opacity: .5;

    mix-blend-mode: overlay;

    animation: rotate randomNum(100, 25, .1s) ease-in-out infinite;

    content: '';

  }

  &:before { background: randomConicGradient(); }

  &:after {

    background: randomConicGradient();

    animation-duration: randomNum(100, 25, .1s);

    animation-direction: reverse;

  }

}

​

@keyframes rotate { 

    to { 

        transform: rotate(1turn); 

    } 

}