CSS3---10.边框阴影

       /* div{
             200px;
            height: 200px;
            background-color: orange;
            margin:100px auto;
            !*添加边框阴影*!
            box-shadow: -10px 10px 5px 0px rgba(0,0,150,0.2) inset,10px -10px 5px 0px rgba(0,0,150,0.2) inset;
        }*/

        /*需求：为前面四个图片盒子添加右下角的外阴影，为最后个盒子添加四个方向的内阴影*/