bulma/docs/_includes/components/categories.html

<nav id="categories" class="bd-categories">
  {% for category in site.data.links.categories %}
    {% assign category_id = category[0] %}
    {% assign category_links = category[1] %}
    {% assign category_link = site.data.links.by_id[category_id] %}

    <div class="bd-category {% if category_id == current_category %}is-active{% endif %}">
      <header class="bd-category-header">
        <a class="bd-category-toggle">
          <span class="icon">
            <i class="fas fa-chevron-down"></i>
          </span>
        </a>
        <a class="bd-category-name {% if category_id == current_link_id %}is-active{% endif %}" href="{{ site.url }}{{ category_link.path }}">
          <strong>{{ category_link.name }}</strong>
        </a>
      </header>

      <ul class="bd-category-list">
        {% for link_id in category_links %}
          {% assign link = site.data.links.by_id[link_id] %}
          <li {% if link_id == current_link_id %}class="is-current"{% endif %}>
            <a href="{{ site.url }}{{ link.path }}">
              {{ link.name }}
            </a>
          </li>
        {% endfor %}
      </ul>
    </div>
  {% endfor %}
</nav>