我希望导航栏固定在顶部但不是固定在机身顶部，而是从我页面中间的容器顶部但是它转到首页，我想要一个Navbar固定在顶部但不是顶部的身体，但从我的页面中间的容器顶部，但它转到首页
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<style>
body {
position: relative;
}
#section1 {padding-top:50px;height:500px;color: #fff; background-color: #1E88E5;}
#section2 {padding-top:50px;height:500px;color: #fff; background-color: #673ab7;}
#section3 {padding-top:50px;height:500px;color: #fff; background-color: #ff9800;}
#section41 {padding-top:50px;height:500px;color: #fff; background-color: #00bcd4;}
#section42 {padding-top:50px;height:500px;color: #fff; background-color: #009688;}
</style>
</head>
<body data-spy="scroll" data-target=".navbar" data-offset="50">
<nav class="navbar navbar-inverse navbar-fixed-top">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">WebSiteName</a>
</div>
<div>
<div class="collapse navbar-collapse" id="myNavbar">
<ul class="nav navbar-nav">
<li><a href="#section1">Section 1</a></li>
<li><a href="#section2">Section 2</a></li>
<li><a href="#section3">Section 3</a></li>
<li class="dropdown"><a class="dropdown-toggle" data-toggle="dropdown" href="#">Section 4 <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="#section41">Section 4-1</a></li>
<li><a href="#section42">Section 4-2</a></li>
</ul>
</li>
</ul>
</div>
</div>
</div>
</nav>
<div id="section1" class="container-fluid">
<h1>Section 1</h1>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
</div>
<div id="section2" class="container-fluid">
<h1>Section 2</h1>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
</div>
<div id="section3" `enter code here`class="container-fluid">
<h1>Section 3</h1>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
</div>
<div id="section41" class="container-fluid">
<h1>Section 4 Submenu 1</h1>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
</div>
<div id="section42" class="container-fluid">
<h1>Section 4 Submenu 2</h1>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
<p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p>
</div>
</body>
</html>