CSS:何制作一个向各个方向延展box?

能在所有主流浏览器中工作.
在垂直和水平方向上延展.
用一个单独的背景图片.

.box {
width: 35em;
margin: 50px auto;
}

<div class="box">
<div class="topleft">
<div class="topright">
<div>
CONTENT GOES HERE
</div>
</div>
</div>
<div class="bottomleft">
<div class="bottomright">
</div>
</div>
</div>

.box div.topleft {
display: block;
background: url("images/box-bg.png") top left no-repeat white;
padding: 2.0em 0em 0em 2.0em;
}
.box div.topright {
display: block;
background: url("images/box-bg.png") top right no-repeat white;
padding: 2.0em;
margin: -2.0em 0 0 2.0em;
}
.box div.bottomleft {
display: block;
height: 45px;
margin-top: -2.0em;
background: url("images/box-bg.png") bottom left no-repeat white;
}
.box div.bottomright {
display: block;
background: url("images/box-bg.png") bottom right no-repeat white;
height: 45px;
margin-left: 3.0em;
}