<nav class="navbar navbar-expand-sm bg-secondary navbar-dark">
  <div class="container-fluid">
    <a class="navbar-brand" href="#"><img src="img/ubuntu-512.png" style="width: 32px;"></a>
    <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#collapsibleNavbar">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="collapsibleNavbar">
      <ul class="navbar-nav">
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="backEnd/sessionManager.php?op=logOut">Cerrar sesión</a>
        </li>    
      </ul>
    </div>
  </div>
</nav>
