body {
    margin: auto;
    overflow: auto;
    background: linear-gradient(315deg, rgb(0, 0, 0) 3%, rgb(0, 128, 255) 38%, rgb(36, 0, 56) 68%, rgb(45, 4, 122) 98%);
    animation: gradient 20s ease infinite;
    background-size: 400% 400%;
    background-attachment: fixed;
}

@keyframes gradient {
    0% {
        background-position: 0% 0%;
    }
    50% {
        background-position: 100% 100%;
    }
    100% {
        background-position: 0% 0%;
    }
}