body {
    width: 100%;
    height: 100%;
    color: #fff;
    background: linear-gradient(-45deg, #ff0000, #f15411, #e7df05, #60ea11, #03f9f1d9, #002be873, #9700e873, #ff0000f7);
    background-size: 1500% 1500%;
    background-attachment: fixed;
    background-position: center;
    background-repeat: no-repeat;
    -webkit-animation: Gradient 30s ease infinite;
    -moz-animation: Gradient 30s ease infinite;
    animation: Gradient 30s ease infinite;
}
 
@-webkit-keyframes Gradient {
    0% {
        background-position: 0% 50%
    }
    50% {
        background-position: 100% 50%
    }
    100% {
        background-position: 0% 50%
    }
}
 
@-moz-keyframes Gradient {
    0% {
        background-position: 0% 50%
    }
    50% {
        background-position: 100% 50%
    }
    100% {
        background-position: 0% 50%
    }
}
 
@keyframes Gradient {
    0% {
        background-position: 0% 50%
    }
    50% {
        background-position: 100% 50%
    }
    100% {
        background-position: 0% 50%
    }
}