body {
	background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab,#23d5ab, #ee7752, #e73c7e, #23a6d5, #23d5ab);
	background-size: 244% 333%;
	animation: gradient 5s linear infinite;
	height: 100vh;
}

@keyframes gradient {
	100% {
		background-position: 100% 100%;
	}
}
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External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/5.0.2/css/bootstrap.min.css
  2. https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.4/css/all.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.