html,body{
    margin:0;
    padding:0;
    overflow-x:hidden;
    height:100%;
}
#dmContainer{
    width:100vw;
    min-height:100vh !important;
    margin:0 auto;
    padding:0;
    position:relative;
    overflow:hidden;
    /* 宽最大600px，高度100%铺满屏幕上下 */
    background-size:min(600px,96vw) 100vh;
    background-position:center top; /* 水平居中、顶部贴边，上下无留白 */
    background-repeat:no-repeat !important;
    background-color:#000;/*左右空余位置黑色*/
}
.dm-item{
  position:absolute;
  right:25%;
  background: rgba(0, 0, 0, 0.1);
  color:#fff;
  padding:4px 11px;
  border-radius:99px;
  font-size:14px;
}
.dm-itema{
  position:absolute;
  right:0;
  background: rgba(0, 0, 0, 0.1);
  color:#fff;
  padding:4px 11px;
  border-radius:99px;
  font-size:14px;
}