{#
  Where the current page sits in the nav. A reader who arrived from a search
  engine lands with no context at all, and on a narrow screen the sidebar that
  would have supplied it is behind the hamburger.

  `page.ancestors` is MkDocs core — nearest parent first, so it is reversed
  here. A section carries a `url` only when something folded an index page into
  it, mkdocs-section-index being the usual cause; without one it has no page to
  link to and renders as plain text, the way partials/nav-item.html treats the
  same case.

  A page with no ancestors is already at the top of the tree: a trail holding
  only itself says nothing, so the bar is left out entirely.
#}
{%- if page and page.ancestors %}
  <nav class="primer-breadcrumbs" aria-label="{% trans %}Breadcrumb{% endtrans %}">
    <ol class="primer-breadcrumbs-list">
      {%- for ancestor in page.ancestors | reverse %}
        <li class="primer-breadcrumbs-item">
          {%- if ancestor.url %}
            <a href="{{ ancestor.url | url }}">{{ ancestor.title }}</a>
          {%- else %}
            <span>{{ ancestor.title }}</span>
          {%- endif %}
        </li>
      {%- endfor %}
      {# The last crumb is where the reader already is, so it is not a link. #}
      <li class="primer-breadcrumbs-item">
        <span class="primer-breadcrumbs-current" aria-current="page">{{ page.title }}</span>
      </li>
    </ol>
  </nav>
{%- endif %}