Navbar崩溃不起作用，虽然它喜欢我做的一切都是正确的

Question

由于某种原因，导航栏不会展开，它仍然处于折叠状态。但我无法在代码中发现任何错误。可能是什么问题？

这是我在页面中包含的内容：

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

<!-- Optional theme -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap-theme.min.css" integrity="sha384-rHyoN1iRsVXV4nD0JutlnGaslCJuC7uwjduW9SVrLvRYooPp2bWYgmgJQIXwl/Sp" crossorigin="anonymous">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.5.2/animate.min.css">

<link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='style.css') }}">

<script src="https://use.fontawesome.com/4f2cdffc79.js"></script>


<nav class="navbar navbar-default">
<div class="container-fluid">
    <div class="navbar-header">
        <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
        </button>
        <a style="font-weight: normal;" href="#" class="navbar-brand"> LANDING PAGE</a>
    </div>
    <div class="collapse navbar-collapse">
        <ul class="nav navbar-nav navbar-right">
            <li><a href="#"> INDUSTRIES </a></li>
            <li><a href="#"> OUR TEAM </a></li>
            <li><a href="#"> CONTACT </a></li>
            <li><a href="#"> BLOG </a></li>
            <li><a href="#"> LOGIN </a></li>
            <li><a href="#"> PLANS & PRICING </a></li>
        </ul>
    </div>
</div>