_navbar.html

<nav class="navbar navbar-expand-md navbar-dark bg-dark">
    <div class="mx-auto order-0">
        <a class="navbar-brand mx-auto" href="#">Blog</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".dual-collapse2">
            <span class="navbar-toggler-icon"></span>
        </button>
    </div>
    <div class="navbar-collapse collapse w-100 order-3 dual-collapse2">
        <ul class="navbar-nav ml-auto">
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                  Dropdown
                </a>
                <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                  <a class="dropdown-item" href="#">Action</a>
                  <a class="dropdown-item" href="#">Another action</a>
                  <div class="dropdown-divider"></div>
                  <a class="dropdown-item" href="#">Something else here</a>
                </div>
              </li>
            </li>
        </ul>
    </div>
</nav>