* {
    box-sizing: border-box;
    padding: 20px;
}

body {
    margin: 0;
    background: radial-gradient(turquoise, pink, yellow, palegreen);
    background-size: 400% 400%;
    width: 100%;
    height: 100vh;
    animation: animate 15s ease infinite;
}

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