<!-- <style>
.box1{
float:left;
width:100px;
background:#ffd900;
margin-right:10px;
padding:10px;
}
.box2{
position: relative;
left:-50px;
top:30px;
width:300px;
background;#0094ff;
float:left;
padding:20px;
}
</style>
<div class="box1">박스1</div>
<div calss="box2">박스2</div> -->
<style>
.box{
width:300px;
background:#0094ff;
}
div#wrapper {
position: relative;
}
#b1 { z-index:1;}
#b2 { z-index:3;}
#b3 { z-index:1;}
</style>
<div id="wrapper">
<div class="box" id="b1">1</div>
<div class="box" id="b2">2</div>
<div class="box" id="b3">3</div>