https://codepen.io/P1N2O/pen/pyBNzX

base.css

body {
	width: 100wh;
	height: 90vh;
	color: #fff;
	background: linear-gradient(-45deg, #EE7752, #E73C7E, #23A6D5, #23D5AB);
	background-size: 400% 400%;
	-webkit-animation: Gradient 15s ease infinite;
	-moz-animation: Gradient 15s ease infinite;
	animation: Gradient 15s ease infinite;
}

@-webkit-keyframes Gradient {
	0% {
		background-position: 0% 50%
	}
	50% {
		background-position: 100% 50%
	}
	100% {
		background-position: 0% 50%
	}
}

@-moz-keyframes Gradient {
	0% {
		background-position: 0% 50%
	}
	50% {
		background-position: 100% 50%
	}
	100% {
		background-position: 0% 50%
	}
}

@keyframes Gradient {
	0% {
		background-position: 0% 50%
	}
	50% {
		background-position: 100% 50%
	}
	100% {
		background-position: 0% 50%
	}
}

h1,
h6 {
	font-family: 'Open Sans';
	font-weight: 300;
	text-align: center;
	position: absolute;
	top: 45%;
	right: 0;
	left: 0;
}