<div id="main_display" class="container-fluid nopadding">
<header>
  <nav id="header" class="navbar fixed-top navbar-expand-lg navbar-dark bg-nav transition">
    <div id="header-container" class="container">

      <a id="brand" class="navbar-brand" href="#"><img src="images/logo_white.png" style="height:70px;"></a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>

    <div class="collapse navbar-collapse justify-content-end" id="navbarSupportedContent">
        <ul class="navbar-nav">
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Om Corax</a>

                <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                    <a class="nav-link dropdown-item" href="#">subpage</a>
                    <a class="nav-link dropdown-item" href="#">subpage</a>
                    <a class="nav-link dropdown-item" href="#">subpage</a>
                </div>
            </li>

<nav id="header" class="navbar fixed-top navbar-expand-lg navbar-dark bg-nav transition">
        <div id="header-container" class="container">
            <a id="brand" class="navbar-brand" href="<?php bloginfo( 'url' ); ?>"><img src="<?php echo get_template_directory_uri(); ?>/images/logo_white.png" style="height:90px;"></a>
            <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
                <span class="navbar-toggler-icon"></span>
            </button>

            <div class="collapse navbar-collapse justify-content-end" id="navbarSupportedContent">

            <?php
            wp_nav_menu( array(
                'theme_location' => 'primary',
                'menu_id'        => 'header',
                'container'      => false,
                'depth'          => 2,
                'menu_class'     => 'navbar-nav',
                'walker'         => new Bootstrap_NavWalker(),
                'fallback_cb'    => 'Bootstrap_NavWalker::fallback',
            ) );
            ?>