.index .section_5 .content .bd .model{
    position: absolute;
    left: 0px;
    top: 0px;
    width: 100%;
        visibility: hidden;
    opacity: 0;
    z-index: -1;
    top: 20px;

-webkit-transition:all 0.2s;
-o-transition:all 0.2s;
-moz-transition:all 0.2s;
-ms-transition:all 0.2s;
transition:all 0.2s;
}