{% macro links(items) %}
<ul class="publication-nav__list">
  {% for item in items %}
  <li{% if item.children %} class="publication-nav__section"{% endif %}>
    {% if item.children %}
      <span class="publication-nav__section-title">{{ item.title }}</span>
      {{ links(item.children) }}
    {% else %}
      <a class="publication-nav__link{% if item == page %} md-nav__link--active{% endif %}" href="{{ item.url | url }}"{% if item == page %} aria-current="page"{% endif %}>{{ item.title }}</a>
    {% endif %}
  </li>
  {% endfor %}
</ul>
{% endmacro %}
<nav class="md-nav md-nav--primary" aria-label="Publication">
  <div class="publication-drawer__heading">
    <span id="publication-navigation-title">Explore the collection</span>
    <button class="publication-drawer__close md-icon" type="button" aria-label="Close navigation">
      {% include ".icons/material/close.svg" %}
    </button>
  </div>
  {{ links(nav.items) }}
</nav>