#bk{
    display: block;
    margin: auto;
    max-width: 100vw;
    max-height: 100vh;
    background-color: black;
}
body,html{
    margin: 0px;
    padding: 0px;
    background-color: black;
}
#cnt{
    position: fixed;
    font-family: "Courier New";
    top: 90px;
    right: 90px;
    width: 100px;
    height: 150px;
    color: rgba(71, 204, 47,0.5);
    background-color: rgba(8, 47, 1,0.5);
    padding: 10px;
}
#score{
    overflow-wrap: break-word;  
}
#mr{
    background-image: url("mr.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    width: 6vw;
    height: 6vw;
    left: 30vw;
    bottom: 6vw;
    position: fixed;
    z-index: 300;
}
button{
    -webkit-user-select: none;     /* 禁止文字被选中 */
    -webkit-touch-callout: none;   /* 禁止长按图片菜单 */
    user-select: none;
    all: unset;           /* 清除浏览器默认样式 */
    display: block;       /* 如果之前 div 是块级，就改成 block */
    cursor: pointer;      /* 鼠标变小手 */
}
#ml{
    background-image: url("ml.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    width: 6vw;
    height: 6vw;
    left: 18vw;
    bottom: 6vw;
    position: fixed;
    z-index: 300;
}
#st{
    background-image: url("st.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    width: 6vw;
    height: 6vw;
    right: 18vw;
    bottom: 6vw;
    position: fixed;
    z-index: 300;
}
@media screen and (max-width:1000px){
    #mr,#ml,#st{
        display: block;
    }
}
@media screen and (min-width:1000px){
    #mr,#ml,#st{
        display: none;
    }
}