body {
    margin: 0;
    padding: 0;
    color: rgba(255, 255, 255, 0.87);
    background-color: #0a0e18;
}

#app {
    width: 100%;
    height: 100vh;
    /* The visible height on phones, where 100vh can include the space
       behind the browser's address bar and hide the bottom of the game. */
    height: 100dvh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* No text selection, callout or tap highlight on the game: a long press on
   the canvas is a game gesture (the hidden level skip). */
canvas {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}