body {
    margin: 0;
    overflow: hidden;
    background-color: #000;
}

canvas {
    display: block;
}

.serve-btn {
    position: absolute;
    top: 20px;
    left: 20px;
    padding: 10px 20px;
    font-size: 16px;
    z-index: 1;
    cursor: pointer;
}

.marbles-btn {
    position: absolute;
    top: 20px;
    left: 120px;
    /* Positioned to the right of the serve button */
    padding: 10px 20px;
    font-size: 16px;
    z-index: 1;
    cursor: pointer;
}