.tip_box{position:fixed;top:50%;right:auto;bottom:auto;left:50%;-webkit-transform:translate(-50%,-50%);transform:translate(-50%,-50%);display:inline-block;min-width:2rem;max-width:7rem;text-align:left;padding:.26rem;border-radius:.04rem;font-size:.28rem;color:#ccc;background-color:rgba(0,0,0,.8);box-sizing:content-box}