//圣杯布局-wrap设置padding/left right加相对定位
<!DOCTYPE html>
<html lang="zh-CN">
<html>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
<title></title>
<style>
*{margin:0; padding:0;}
.wrap{padding:0 200px; overflow: hidden}
.main{100%; background:#57ccb1; float:left; height:100px;}
.left{ float:left;margin-left:-100%; 200px; height:100px; background:#ff3f27; position:relative; left:-200px;}
.right{ float:left;margin-left:-200px; 200px; height:100px; background:#fbb800; position:relative;right:-200px;}
</style>
</head>
<body>
<div class="wrap">
<div class="main">main</div>
<div class="left">left</div>
<div class="right">right</div>
</div>
</body>
</html>
//双飞翼布局-在main中嵌套一层设置margin
<!DOCTYPE html>
<html lang="zh-CN">
<html>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
<title></title>
<style>
*{margin:0; padding:0;}
.main{100%; background:#57ccb1; float:left; height:100px;}
.left{ float:left;margin-left:-100%;opacity:0.4; 200px; height:100px; background:#ff3f27; }
.right{ float:left;margin-left:-200px;opacity:0.4; 200px; height:100px; background:#fbb800; }
.main_con{margin-left:200px; margin-right:200px;}
</style>
</head>
<body>
<div class="wrap">
<div class="main">
<div class="main_con">main</div>
</div>
<div class="left">left</div>
<div class="right">right</div>
</div>
</body>
</html>