/* 页面尺寸大道与769px */
@media screen and (min-width:769px){
    .parent,
    .big_video{
        width:  450px;
        height: 450px;
        position: absolute;
        float: left;
        background-size: 451px 451px;
        top: 0%;
        left: 100px;
    }
    
    .child{
        width: 250px;
        height: 250px;
        border: 1px solid blue;
        position: absolute;
        display: none;
        z-index: 2;
    }
    
    .showBox{
        width: 600px;
        height: 600px;
        border: 1px solid green;
        float: left;
        margin-left: 10px;
        overflow: hidden;
        position: absolute;
        display: none;
        top: 0%;
        left: 560px;
    }
    
    .show{
        width: 1200px;
        height: 1200px;
        float: left;
        background-size:1200px 1200px;
        /*transform: scale(3,3);*/
        /*margin-left: 50px;*/
        position: absolute;
        bottom: 0;
        right: 0;
    }
}


/* 页面尺寸大道与769px */
@media screen and (max-width:768px){
    .parent,
    .big_video{
        width:  450px;
        height: 450px;
        border: 1px solid red;
        position: absolute;
        float: left;
        background-size: 451px 451px;
        top: 0%;
        left: 100px;
        display: none;
    }
}

.play_video{
    max-width: 100%;
    width: 100%;
    height: 100%;
}