body {
    background: linear-gradient(270deg, #22a583, #c862cb);
    background-size: 400% 400%;

    -webkit-animation: AnimationName 30s ease infinite;
    -moz-animation: AnimationName 30s ease infinite;
    animation: AnimationName 30s ease infinite;
}

@-webkit-keyframes AnimationName {
    0%{background-position:0% 50%}
    50%{background-position:100% 50%}
    100%{background-position:0% 50%}
}
@-moz-keyframes AnimationName {
    0%{background-position:0% 50%}
    50%{background-position:100% 50%}
    100%{background-position:0% 50%}
}
@keyframes AnimationName {
    0%{background-position:0% 50%}
    50%{background-position:100% 50%}
    100%{background-position:0% 50%}
}

.shark {
    position: absolute;
    left: 50%;
    top: 50%;
}