<h1>Pure CSS3 Animated Gradient Background</h1>

body {
    width: 100wh;
    height: 90vh;
    color: #f5eeee;
    background: linear-gradient(
-45deg
, #f1744e, #e42c73, #17a3d6, #18d6a9);
    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;
}