如何在Bootstrap中让面板标题“固定”在顶部？

<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>

<nav class="navbar navbar-default navbar-fixed-top">
  <div class="container">
    <!-- 导航栏内容 -->
  </div>
</nav>

<div class="panel panel-default">
  <div class="panel-heading">
    <h3 class="panel-title">面板标题</h3>
  </div>
  <div class="panel-body">
    <!-- 面板内容 -->
  </div>
</div>