bootstrap实现嵌套列

<!DOCTYPE html>
<html>
<head>
   <title>Bootstrap 实例 - 嵌套列</title>
   <link href="/bootstrap/css/bootstrap.min.css" rel="stylesheet">
   <script src="/scripts/jquery.min.js"></script>
   <script src="/bootstrap/js/bootstrap.min.js"></script>
</head>
<body>

<div class="container">

   <h1>Hello, world!</h1>

   <div class="row">

      <div class="col-md-3" style="background-color: #dedef8;box-shadow:
         inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
         <h4>第一列</h4>
         <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
      </div>

      <div class="col-md-9" style="background-color: #dedef8;box-shadow:
         inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
         <h4>第二列 - 分为四个盒子</h4>
         <div class="row">
            <div class="col-md-6" style="background-color: #B18904;
               box-shadow: inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
               <p>Consectetur art party Tonx culpa semiotics. Pinterest
                  assumenda minim organic quis.
               </p>
            </div>
            <div class="col-md-6" style="background-color: #B18904;
               box-shadow: inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
               <p> sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.
               </p>
            </div>
         </div>

         <div class="row">
            <div class="col-md-6" style="background-color: #B18904;
               box-shadow: inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
               <p>quis nostrud exercitation ullamco laboris nisi ut
                  aliquip ex ea commodo consequat.
               </p>
            </div>
            <div class="col-md-6" style="background-color: #B18904;
               box-shadow: inset 1px -1px 1px #444, inset -1px 1px 1px #444;">
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim.</p>
            </div>
         </div>

      </div>

   </div>

</div>

</body>
</html>