如何使烤面包机出现在页面顶部？

Question

我无法让Bootstrap导航栏与Toastr一起使用。烤面包片会在导航栏顶部创建一小段空白，然后消失，但是烤面包片本身不可见。代码如下所示。任何帮助表示赞赏。

我刚刚注意到样式表链接是问题的原因

    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS" crossorigin="anonymous">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous">

    <script>
  toastr.options = {
    "closeButton": true,
    "debug": false,
    "newestOnTop": false,
    "progressBar": true,
    "positionClass": "toast-top-right",
    "preventDuplicates": false,
    "onclick": null,
    "showDuration": "3000",
    "hideDuration": "1000",
    "timeOut": "5000",
    "extendedTimeOut": "1000",
    "showEasing": "swing",
    "hideEasing": "linear",
    "showMethod": "fadeIn",
    "hideMethod": "fadeOut"
  }
  toastr.info('Are you the 6 fingered man?')
</script>




<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNav">
    <ul class="navbar-nav">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricing</a>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
      </li>
    </ul>
  </div>
</nav>