.pic {
position:relative;
background:#CCC;
margin:10px;
}
.pic span {
display:block;
border:1px solid #333;
background:#FFF;
position:relative;
padding: 3px;
}
.right {/*阴影在右边时*/
top:-4px;
left:-4px;
}
.left {/*阴影在左边时*/
top:-4px;
right:-4px;
}
]
]