.img-mask{position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,.85);display:none;z-index:9999}
.img-mask img{position:absolute;top:50%;left:50%;max-width:90%;max-height:90%;transform:translate(-50%,-50%) scale(0.8);transition:all .3s;}
.img-mask.show img{transform:translate(-50%,-50%) scale(1)}
.img-close{position:absolute;top:30px;right:40px;font-size:40px;color:#fff;cursor:pointer}