为什么不显示导航栏项目？

Question

我有以下代码，除了Mona Jalal 和右上角旁边的一个白色小按钮，没有其他显示：

<div class="container-fluid">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#nav-main">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <a class="navbar-brand" href="index.html">Mona Jalal</a>
            </div>

            <div class="collapse navbar-collapse" id="nav-main">
                <ul class="nav navbar-nav">
                    <li><a class="nav-item nav-link active page-item" href="index.html">Mona Jalal <span class="sr-only">(current)</span></a></li>
                    <li><a class="nav-item nav-link page-item" href="education.html">Education</a></li>
                    <li><a class="nav-item nav-link page-item" href="coursework.html">Coursework</a></li>
                    <li><a class="nav-item nav-link page-item" href="teaching.html">Teaching</a></li>
                    <li><a class="nav-item nav-link page-item" href="projects.html">Projects</a></li>
                    <li><a class="nav-item nav-link page-item" href="honors.html">Honors & Awards</a></li>
                    <li><a class="nav-item nav-link page-item" href="experience.html">Experience</a></li>
                </ul>
                <ul class="nav navbar-nav navbar-right">

                    <li><a class="navbar-brand pull-sm-right" href="https://github.com/monajalal"><i class="fa fa-github fa-lg"></i></a></li>
                    <li><a class="navbar-brand pull-sm-right" href="https://twitter.com/MonaJalal_"><i class="fa fa-twitter fa-lg"></i></a></li>
                    <li><a class="navbar-brand pull-sm-right" href="https://www.linkedin.com/in/mona-jalal"><i class="fa fa-linkedin fa-lg"></i></a></li>
                    <li><a class="navbar-brand pull-sm-right" href="http://stackoverflow.com/users/2414957/mona-jalal"><i class="fa fa-stack-overflow fa-lg"></i></a></li>
                    <li><a class="navbar-brand pull-sm-right" href="mailto:jalal@cs.wisc.edu"><i class="fa fa-envelope fa-lg" aria-hidden="true"></i></a></li>
                    <li><a class="navbar-brand pull-sm-right" href="https://www.instagram.com/mona_of_green_gables"><i class="fa fa-instagram fa-lg"></i></a></li>

                </ul>
            </div>
        </div>

我首先有以下代码，它有效，但是当我将屏幕宽度缩小很多时，事情变得很奇怪，所以我决定使用一个按钮，如果你点击它会显示项目（比如在移动设备中或者说你看到的按钮在 Chrome 的右角，三行）。下面的代码实际上有效，但我说的那个问题。我有点迷茫，所以如果你能给我一些提示，那就太好了:)

<div class="container">
    <nav class="navbar navbar-dark bg-primary navbar-fixed-top">
        <div class="nav navbar-nav">
            <a class="nav-item nav-link page-item" href="index.html">Mona Jalal <span class="sr-only">(current)</span></a>
            <a class="nav-item nav-link active page-item" href="education.html">Education</a>
            <a class="nav-item nav-link page-item" href="coursework.html">Coursework</a>
            <a class="nav-item nav-link page-item" href="teaching.html">Teaching</a>
            <a class="nav-item nav-link page-item" href="projects.html">Projects</a>
            <a class="nav-item nav-link page-item" href="honors.html">Honors & Awards</a>
            <a class="nav-item nav-link page-item" href="experience.html">Experience</a>
            <a class="navbar-brand pull-sm-right m-r-0" href="https://github.com/monajalal"><i class="fa fa-github fa-lg"></i></a>
            <a class="navbar-brand pull-sm-right m-r-2" href="https://twitter.com/MonaJalal_"><i class="fa fa-twitter fa-lg"></i></a>
            <a class="navbar-brand pull-sm-right m-r-4" href="https://www.linkedin.com/in/mona-jalal"><i class="fa fa-linkedin fa-lg"></i></a>
            <a class="navbar-brand pull-sm-right m-r-6" href="http://stackoverflow.com/users/2414957/mona-jalal"><i class="fa fa-stack-overflow fa-lg"></i></a>
            <a class="navbar-brand pull-sm-right m-r-8" href="mailto:jalal@cs.wisc.edu"><i class="fa fa-envelope fa-lg" aria-hidden="true"></i></a>
            <a class="navbar-brand pull-sm-right m-r-10" href="https://www.instagram.com/mona_of_green_gables"><i class="fa fa-instagram fa-lg"></i></a>
        </div>
    </nav>
</div>

如果您需要更多详细信息或问题不够清楚，请告诉我。

更新：对于第二个正在运行的示例，问题是当我减小屏幕宽度时，它恰好是这样的，因为我是 bootstrap/CSS 的新手，我不确定什么是正确的术语来描述问题，但我想照片显示得最好！

Answer 1

这可能是由应用于“nav-main”div 的“collapse navbar-collapse”CSS 类引起的。查看 bootstrap 文档，了解有关默认导航栏 (http://getbootstrap.com/components/#navbar-default) 的任何重要说明是否适用于您的情况。