导航栏折叠但汉堡包图标不显示菜单

Question

这是fCC的致敬页面项目，所以问题是导航栏崩溃了，除了汉堡包图标以外的所有图标都没有显示菜单，data-spy="affix"无法正常工作请求帮助。 这是codepen页面：https://codepen.io/HatimShady/full/Nyxaqm/

<nav data-spy="affix"  class=" navbar navbar-default">
    <div class="container">
        <div class="navbar-header">
            <button class="navbar-toggle collapsed" type="button" data-toggle="collapse" data-target="#collapsemenu">
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="#intro">Tribute: Alan Turing</a>
        </div>
        <div id="collapsemenu" class="collapse navbar-collapse">
            <ul class="nav navbar-right navbar-nav">
            <li><a href="#synopsis">Synopsis</a></li>
            <li><a href="#early-life">Early Life</a></li>
            <li><a href="#caec">Cryptanalysis and Early Computers</a></li>
            <li><a href="#death">Death</a></li>
            <li><a href="#rec">Awards, Recognition and Royal Pardon</a></li>
            </ul>
        </div>
    </div>