html, body {
    width: 100%;
    height: 100%;
}

body {
    background: linear-gradient(-45deg, #52eee9, #1140e8, #30c1f6, #043a8b);
    background-size: 400% 400%;
    animation: gradient 30s ease infinite;
}

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