="Toggle navigation">
          <span class="navbar-toggler-icon"></span>
        </button>

        <div class="collapse navbar-collapse" id="navbarNavDropdown">

          <!-- Left nav -->
          <ul class="nav navbar-nav mr-auto">
            <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="#">Link</a></li>
            <li class="nav-item dropdown"><a c