*{
    margin:0;
    padding:0;
    cursor:url("../img/mouse.png"),auto;        /*鼠标改用图片*/
}
#container{
    width:100%;
    height:100%;
    margin:auto;
    margin-top: 30px;
    margin-bottom: 0;
    text-align: center;
}
#canvas{
    border:1px solid #c4c4c4;
}
#startBTN{                  /*开始游戏按钮样式*/
    position: absolute;
    left:50%;
    top:50%;
    transform: translate(-50%,-50%);
}