GradientAnimator

.css-selector {
    background: linear-gradient(247deg, #66d5f7, #28b4c7, #2c93e8, #76c1ff);
    background-size: 800% 800%;
    -webkit-animation: AnimationName 16s ease infinite;
    -moz-animation: AnimationName 16s ease infinite;
    -o-animation: AnimationName 16s ease infinite;
    animation: AnimationName 16s ease infinite;
}
@-webkit-keyframes AnimationName {
    0%{background-position:0% 78%}