I designed a new theme in WordPress. I used Bootstrap Menu bar for responsive design but shows up a toggle in Desktop Mode.

<div id="nav">
<nav class="navbar navbar-default navbar-fixed-top" role="navigation">
  <div class="container">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>          
    </div>
    <?php
    wp_nav_menu( array(
            'menu'              => 'top-menu',
            'depth'             => 2,
            'container'         => 'div',
            'container_class'   => 'navbar-collapse collapse',
            'menu_class'        => 'nav navbar-nav',
            'fallback_cb'       => 'wp_bootstrap_navwalker::fallback',
            'walker'            => new wp_bootstrap_navwalker())
        );
    ?>
  </div><!-- /.container-fluid -->
</nav>

add_theme_support('menu');
require_once('wp-bootstrap-navwalker.php');
register_nav_menus(
   array(
        'top-menu' => 'Top Menu Location',
         'mobile-menu' => 'Mobile Menu Location',
      ));