body {
    margin: 0;
    min-height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    gap: 6px;

    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 18px;
    line-height: 1.25;
    color: #fff;
    background:
        linear-gradient(rgba(0,0,0,.6), rgba(0,0,0,.6)),
        url("tile.png");

    background-repeat: repeat, repeat;

    /* Scale 1024x1024 tile down to 512x512 */
    background-size: auto, 512px 512px;

    animation: scroll 8s linear infinite;
}

@keyframes scroll {
    from {
        background-position: 0 0, 0 0;
    }
    to {
        background-position: 0 0, 512px 512px;
    }
}