.css-selector {
    background: linear-gradient(54deg, #eae7e7, #c9e6e6, #eedfed, #dfeedc);
    background-size: 800% 800%;

    -webkit-animation: Gradient_backgrund 16s ease infinite;
    -moz-animation: Gradient_backgrund 16s ease infinite;
    animation: Gradient_backgrund 16s ease infinite;
}

@-webkit-keyframes Gradient_backgrund {
    0%{background-position:0% 45%}
    50%{background-position:100% 56%}
    100%{background-position:0% 45%}
}
@-moz-keyframes Gradient_backgrund {
    0%{background-position:0% 45%}
    50%{background-position:100% 56%}
    100%{background-position:0% 45%}
}
@keyframes Gradient_backgrund {
    0%{background-position:0% 45%}
    50%{background-position:100% 56%}
    100%{background-position:0% 45%}
}