{# Single-row header: logo · centred nav tabs · search + palette toggle #}
<header class="md-header" data-md-component="header">
  <nav class="md-header__inner md-grid" aria-label="Header">

    {# AIRS purple dot logo #}
    <a href="{{ config.extra.homepage | d(nav.homepage.url, true) | url }}"
       class="airs-dot" aria-label="AIRS Home">AIRS</a>

    {# Mobile drawer toggle #}
    <label class="md-header__button md-icon" for="__drawer">
      {% set icon = config.theme.icon.menu or "material/menu" %}
      {% include ".icons/" ~ icon ~ ".svg" %}
    </label>

    {# Logo #}
    <a
      href="{{ config.extra.homepage | d(nav.homepage.url, true) | url }}"
      title="{{ config.site_name | e }}"
      class="md-header__button md-logo"
      aria-label="{{ config.site_name }}"
    >
      {% include "partials/logo.html" %}
    </a>

    {# Inline nav tabs — visible on desktop only #}
    {# Macro: drill into nested sections to find the first actual page #}
    {% macro first_page_url(item) %}
      {%- if item.url -%}
        {{ item.url | url }}
      {%- elif item.children -%}
        {{ first_page_url(item.children[0]) }}
      {%- endif -%}
    {% endmacro %}
    <ul class="md-header-tabs">
      {% for nav_item in nav %}
      <li class="md-header-tabs__item">
        <a
          href="{% if nav_item.title == 'Home' %}{{ nav.homepage.url | url }}{% else %}{{ first_page_url(nav_item) | trim }}{% endif %}"
          class="md-header-tabs__link{% if nav_item.active %} md-header-tabs__link--active{% endif %}"
        >
          {{ nav_item.title }}
        </a>
      </li>
      {% endfor %}
    </ul>

    {# Colour-scheme toggle #}
    {% if config.theme.palette %}
      {% if not config.theme.palette is mapping %}
        <div class="md-header__option">
          {% include "partials/palette.html" %}
        </div>
      {% endif %}
    {% endif %}

    {# Search #}
    {% if "search" in config.plugins %}
      <label class="md-header__button md-icon" for="__search">
        {% set icon = config.theme.icon.search or "material/magnify" %}
        {% include ".icons/" ~ icon ~ ".svg" %}
      </label>
      {% include "partials/search.html" %}
    {% endif %}

  </nav>
</header>