单击时导航栏变色

如何解决单击时导航栏变色

我的问题：我正在尝试导航栏：

     <Meta charset="UTF-8">
    <Meta name="viewport" content="width=device-width,initial-scale=1.0">
    <title>Vérité Ou Pas ?</title>
    <!--<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5paxtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">-->
    <link rel="stylesheet" href="https://bootswatch.com/4/lux/bootstrap.min.css">
    <link rel="stylesheet" href="/CSS/header.css">
   
    
</head>
<body>

<nav class="navbar navbar-expand-lg navbar-dark bg-primary">
  <a class="navbar-brand" href="<?PHP URL ?>index.PHP">WatTheFolk ?</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor01" aria-controls="navbarColor01" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarColor01">
    <ul class="navbar-nav mr-auto">
      <!-- <li class="nav-item active">
        <a class="nav-link" href="<?= URL ?>index.PHP">

...

      <li class="nav-item dropdown">
        <div class="account" > My account</button>    
        <div class="dropdown-menu">
          <a class="dropdown-item" href="compte/create.PHP">Créer un compte</a>
          <a class="dropdown-item" href="compte/connexion.PHP">Se connecter</a>
        </div>
      </li> 

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

<div class="container"> <!-- Ouverture de la balise CONTAINER -->

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="JS/verite.js"></script>

导航栏的下拉菜单不想打开，当我在帐户上尝试：hover / css或在单击带有JS的帐户时发出警报时，它不起作用。为什么会发生？

有人可以帮助我并告诉我我的代码在哪里错误吗？谢谢你。