body {
background: linear-gradient(229deg, #fffc00, #ee2b61, #faa21b, #15f33f, #00f0ff, #570c97, #991a3d, #570c97, #00f0ff, #15f33f, #faa21b, #faa21b, #faa21b, #ee2b61, #fffc00);
background-size: 3000% 3000%;


-webkit-animation: AnimationName 200s ease infinite; -moz-animation: AnimationName 200s ease infinite; animation: AnimationName 200s ease infinite;
}
@-webkit-keyframes AnimationName {
    0%{background-position:56% 0%}
    50%{background-position:45% 100%}
    100%{background-position:56% 0%}
}
@-moz-keyframes AnimationName {
    0%{background-position:56% 0%}
    50%{background-position:45% 100%}
    100%{background-position:56% 0%}
}
@keyframes AnimationName { 
    0%{background-position:56% 0%}
    50%{background-position:45% 100%}
    100%{background-position:56% 0%}
}

.container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translateX(-50%) translateY(-50%);
}