<header class=“navbar navbar-expand-lg navbar-dark bg-primary shadow-sm”>

<nav class="container">
  <!-- site home -->
  <a class="navbar-brand" href="{{ '/' | absolute_url }}">
    <img src="{{ site.logo | relative_url }}" alt="{{ site.title }} logo" height="32" width="32">
  </a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor01"
    aria-controls="navbarColor01" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarColor01">
    <ul class="navbar-nav mr-auto">
      <!-- TODO add theme version dropdown here -->
      {%- for link in site.data.nav.header -%}
        {%- if link.url contains '://' -%}
          {%- assign url = link.url -%}
        {%- else -%}
          {%- assign url = link.url | relative_url -%}
        {%- endif -%}
      <li class="nav-item">
        <a class="nav-link" href="{{ url }}" {% if link.description %} title="{{ link.description }}"
          {% endif %}>{{ link.title }}</a>
      </li>
      {%- endfor -%}
    </ul>
    {% if site.search == true %}
      {%- include search-providers/search_form.html -%}
    {% endif %}
  </div>
</nav>

</header>