魔哥圆角--（代码精简，完全自适应）

<style type="text/css">
body,p,div {margin:0;padding:0;}
.Box {margin:10px auto;width:500px;}
/*淘宝的圆角方法*/
.R-1-T,.R-1-B {height:6px;position:relative;background-image:url(http://images.cnblogs.com/cnblogs_com/jikey/round6.png);background-repeat:no-repeat;overflow:hidden;}
.R-1-T {background-position:-6px 0;margin-bottom:-6px;}
.R-1-B {background-position:-6px -6px;margin-top:-6px;}
.R-1-T b,.R-1-B b {float:right;background-image:url(http://images.cnblogs.com/cnblogs_com/jikey/round6.png);background-repeat:no-repeat;height:6px;width:6px;text-indent:-9999px;}
.R-1-T b {background-position:0 0;}
.R-1-B b {background-position:0 -6px;}
.R-1-C {border:1px solid #dfdfdf;padding:6px;}
</style>
<div class="Box">
<p class="R-1-T"><b>圆角底部</b></p>
<div class="R-1-C">内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里内容在这里</div>
<p class="R-1-B"><b>圆角底部</b></p>
</div>