canvas {
    display: block;
    margin: 50px auto;
    box-shadow: -2px -2px 2px #efefef, 5px 5px 5px #b9b9b9;
    cursor: pointer;
    background-color: #eeeeee;
}

.game-tip {
    text-align: center;
    margin: 20px 0;
    color: #444444;
}