html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

* {
  box-sizing: border-box;
}

:root {
  --size: 15px;
}

body {
  display: grid;
  place-items: center;
  min-height: 100vh;
  background: hsl(240, 11%, 2%);
}

.el {
  background: conic-gradient(from 180deg at 50% 70%,hsla(0,0%,98%,1) 0deg,#eec32d 72.0000010728836deg,#ec4b4b 144.0000021457672deg,#709ab9 216.00000858306885deg,#4dffbf 288.0000042915344deg,hsla(0,0%,98%,1) 1turn);
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  mask:
    radial-gradient(circle at 50% 50%, white 0.5px, transparent 1.5px) 50% 50% / var(--size) var(--size),
    url("https://assets.codepen.io/605876/noise-mask.png") 256px 50% / 256px 256px;
  mask-composite: intersect;
  animation: flicker 20s infinite linear;
}

@keyframes flicker {
  to {
    mask-position: 50% 50%, 0 50%;
  }
}