CSS实现阴影效果

 <STYLE>
.out {
  display:block;
  background:#bbb;
  border:1px solid #ddd;
  position:relative;
  margin:1em 0;
  }
.in {
  text-align:center;
  background:#fff;
  border:1px solid #555;
  position:relative;
  padding:5px;
  font-weight:normal;
  }
.ltin {
  left:-5px;
  }
.tpin {
  top:-5px;
  }
.narrow {width:8em;}
h4 {font-weight:bold; color:#000;}
</STYLE>
<DIV class="out narrow"> <DIV class="in ltin tpin"> <H4>Narrow</H4> <P>This is the text that goes in the middle.</P> </DIV> </DIV>