一些拐角的设计，收藏希望以后可以用到！
?
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" >
<head>
<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
<title>纯CSS模拟不同的拐角效果 - Flywe の Blog</title>
<meta name="Author" content="Stu Nicholls" />
<style type="text/css">
body {background:#e0e0e0;}
/* Inset 3D Raised */
.raised {background: transparent; width:40%;}
.raised h1, .raised p {margin:0 10px;}
.raised h1 {font-size:2em; color:#fff;}
.raised p {padding-bottom:0.5em;}
.raised .b1, .raised .b2, .raised .b3, .raised .b4, .raised .b1b, .raised .b2b, .raised .b3b, .raised .b4b {display:block; overflow:hidden; font-size:1px;}
.raised .b1, .raised .b2, .raised .b3, .raised .b1b, .raised .b2b, .raised .b3b {height:1px;}
.raised .b2 {background:#ccc; border-left:1px solid #fff; border-right:1px solid #eee;}
.raised .b3 {background:#ccc; border-left:1px solid #fff; border-right:1px solid #ddd;}
.raised .b4 {background:#ccc; border-left:1px solid #fff; border-right:1px solid #aaa;}
.raised .b4b {background:#ccc; border-left:1px solid #eee; border-right:1px solid #999;}
.raised .b3b {background:#ccc; border-left:1px solid #ddd; border-right:1px solid #999;}
.raised .b2b {background:#ccc; border-left:1px solid #aaa; border-right:1px solid #999;}
.raised .b1 {margin:0 5px; background:#fff;}
.raised .b2, .raised .b2b {margin:0 3px; border-width:0 2px;}
.raised .b3, .raised .b3b {margin:0 2px;}
.raised .b4, .raised .b4b {height:2px; margin:0 1px;}
.raised .b1b {margin:0 5px; background:#999;}
.raised .boxcontent {display:block; background:#ccc; border-left:1px solid #fff; border-right:1px solid #999;}
/* Inset 3D Curved */
.inset {background: transparent; width:40%;}
.inset h1, .inset p {margin:0 10px;}
.inset h1 {font-size:2em; color:#fff;}
.inset p {padding-bottom:0.5em;}
.inset .b1, .inset .b2, .inset .b3, .inset .b4, .inset .b1b, .inset .b2b, .inset .b3b, .inset .b4b {display:block; overflow:hidden; font-size:1px;}
.inset .b1, .inset .b2, .inset .b3, .inset .b1b, .inset .b2b, .inset .b3b {height:1px;}
.inset .b2 {background:#ccc; border-left:1px solid #999; border-right:1px solid #aaa;}
.inset .b3 {background:#ccc; border-left:1px solid #999; border-right:1px solid #ddd;}
.inset .b4 {background:#ccc; border-left:1px solid #999; border-right:1px solid #eee;}
.inset .b4b {background:#ccc; border-left:1px solid #aaa; border-right:1px solid #fff;}
.inset .b3b {background:#ccc; border-left:1px solid #ddd; border-right:1px solid #fff;}
.inset .b2b {background:#ccc; border-left:1px solid #eee; border-right:1px solid #fff;}
.inset .b1 {margin:0 5px; background:#999;}
.inset .b2, .inset .b2b {margin:0 3px; border-width:0 2px;}
.inset .b3, .inset .b3b {margin:0 2px;}
.inset .b4, .inset .b4b {height:2px; margin:0 1px;}
.inset .b1b {margin:0 5px; background:#fff;}
.inset .boxcontent {display:block; background:#ccc; border-left:1px solid #999; border-right:1px solid #fff;}
/* Curved cutout Borders*/
.curved {background: transparent; width:40%;}
.curved h1, .curved p {margin:0 10px;}
.curved h1 {font-size:2em; color:#fff;}
.curved p {padding-bottom:0.5em;}
.curved .b1, .curved .b2, .curved .b3, .curved .b4 {display:block; overflow:hidden; height:1px; font-size:1px;}
.curved .b2, .curved .b3, .curved .b4 {background:#e0cea3; border-left:1px solid #fff; border-right:1px solid #fff;}
.curved .b1 {margin:0 4px; background:#fff;}
.curved .b2 {margin:0 4px; height:2px;}
.curved .b3 {margin:0 3px;}
.curved .b4 {margin:0; height:1px; border-width:0 3px 0 3px;}
.curved .boxcontent {display:block; background:#e0cea3; border:0 solid #fff; border-width:0 1px;}
/* flared serif */
.serif {background: transparent; width:40%;}
.serif h1, .serif p {margin:0 10px;}
.serif h1 {font-size:2em; color:#fff;}
.serif p {padding-bottom:0.5em;}
.serif .b1, .serif .b2, .serif .b3, .serif .b4 {display:block; overflow:hidden; font-size:1px;}
.serif .b1, .serif .b2, .serif .b3 {height:1px;}
.serif .b2, .serif .b3 {background:#fc0; border-left:1px solid #fff; border-right:1px solid #fff;}
.serif .b4 {background:#fc0; border-left:1px solid #fff; border-right:1px solid #fff;}
.serif .b1 {margin:0; background:#fff;}
.serif .b2 {margin:0 1px; border-width:0 2px;}
.serif .b3 {margin:0 3px;}
.serif .b4 {height:2px; margin:0 4px;}
.serif .boxcontent {display:block; background:#fc0; border-left:1px solid #fff; border-right:1px solid #fff; margin:0 5px;}
/* Pillar type */
.pillar {background: transparent; width:40%;}
.pillar h1, .pillar p {margin:0 10px;}
.pillar h1 {font-size:2em; color:#fff;}
.pillar p {padding-bottom:0.5em;}
.pillar .b1, .pillar .b2, .pillar .b3, .pillar .b4 {display:block; overflow:hidden; font-size:1px;}
.pillar .b1, .pillar .b2, .pillar .b4 {height:1px;}
.pillar .b2, .pillar .b3 {background:#d66; border-left:1px solid #fff; border-right:1px solid #fff;}
.pillar .b4 {background:#d66; border-left:4px solid #fff; border-right:4px solid #fff;}
.pillar .b1 {margin:0 2px; background:#fff;}
.pillar .b2 {margin:0 1px; border-width:0 1px;}
.pillar .b3 {height:2px; margin:0;}
.pillar .b4 {margin:0 2px;}
.pillar .boxcontent {display:block; background:#d66; border-left:1px solid #fff; border-right:1px solid #fff; margin:0 5px;}
</style>
</head>
<body>
<h2 class="bxs">Krazy Korners</h2>
<h3>by Stu Nicholls</h3>
<div class="curved">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>Example 1</h1>
<p>A box with cutout corners</p>
</div>
<b class="b4"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>
<p></p>
<div class="serif">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>Example 2</h1>
<p>Corners to give a serif effect.</p>
</div>
<b class="b4"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>
<p></p>
<div class="pillar">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b2"></b><b class="b4"></b>
<div class="boxcontent">
<h1>Example 3</h1>
<p>Corners to give a rounded pillar effect.</p>
</div>
<b class="b4"></b><b class="b2"></b><b class="b3"></b><b class="b2"></b><b class="b1"></b>
</div>
<p></p>
<div class="raised">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>Example 4</h1>
<p>Rounded corners with raised borders</p>
</div>
<b class="b4b"></b><b class="b3b"></b><b class="b2b"></b><b class="b1b"></b>
</div>
<p></p>
<div class="inset">
<b class="b1"></b><b class="b2"></b><b class="b3"></b><b class="b4"></b>
<div class="boxcontent">
<h1>Example 5</h1>
<p>Rounded corners with inset borders</p>
</div>
<b class="b4b"></b><b class="b3b"></b><b class="b2b"></b><b class="b1b"></b>
</div>
</body>
</html>
?研究一下，这种方式主要是遮罩的形式实现圆角的。