- <li><a href="{{ page.root }}/reference/">Reference</a></li>
- {% for extra in site.extras %}
- <li><a href="{{ page.root }}{{ extra.url }}">{{ extra.title }}</a></li>
+ <li><a href="{{ relative_root_path }}{% link reference.md %}">Referencia</a></li>
+ {% for lesson_extra in lesson_extras %}
+ {% if site.extras_order %}
+ {% assign extra = site.extras | where: "slug", lesson_extra | first %}
+ {% else %}
+ {% assign extra = lesson_extra %}
+ {% endif %}
+ <li><a href="{{ relative_root_path }}{{ extra.url }}">{{ extra.title }}</a></li>