JSFiddle - React, Tailwind, and code Playground

by HDL52

HTML

<div class="box">
  <span></span>
</div>

CSS

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  overflow: hidden;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #fff;
  scale: 0.75;
}

@property --a {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg;
}

.box {
  position: relative;
  width: 400px;
  height: 300px;
}

.box::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-conic-gradient(from var(--a), #0f0, #ff0, #0ff, #f0f, #0ff);
  border-radius: 20px;
  animation: rotating 4s linear infinite;
}

.box::after {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-conic-gradient(from var(--a), #0f0, #ff0, #0ff, #f0f, #0ff);
  border-radius: 20px;
  animation: rotating 4s linear infinite;
  filter: blur(40px);
  opacity: 0.75;
}

.box span{
  position: absolute;
  inset: 4px;
  background: #222;
  border-radius: 16px;
  z-index: 1;
}

@keyframes rotating {
  0% {
    --a: 0deg;
  }
  100% {
    --a: 360deg;
  }
}