my.css

background: linear-gradient(220deg, #25a584, #447fbe, #be4486, #be5e44, #9dad39);
background-size: 1000% 1000%;
-webkit-animation: GiveMeColor 60s ease infinite;
-moz-animation: GiveMeColor 60s ease infinite;
-o-animation: GiveMeColor 60s ease infinite;
animation: GiveMeColor 60s ease infinite;
@-webkit-keyframes GiveMeColor {
    0%{background-position:78% 0%}
    50%{background-position:23% 100%}
    100%{background-position:78% 0%}