.wechat_qrcode {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    display: none;
    z-index: 100;
    background: rgba(0, 0, 0, .6)
}



.wechat_qrcode img {
    position: fixed;
    left: 50%;
    top: 50%;
    margin-left: -1.3rem;
    margin-top: -2.6rem;
    width: 2.6rem;
    height: 5.2rem
}