html, body {
    margin: 0;
    height: 100%;
    overflow: hidden;
    background: #0b6b3a;
    color: #e8f0e8;
    font-family: system-ui, sans-serif;
}

#board {
    /* Fills the window; the canvas inside is sized in JS. */
    height: 100%;
    outline: none;
    -webkit-tap-highlight-color: transparent;

    /* Dragging is driven by pointer events, so the browser must not claim the
       gesture for scrolling/zooming, and a drag must not select the page. */
    touch-action: none;
    user-select: none;
    -webkit-user-select: none;
}

#board canvas {
    display: block;
}