{%- assign page_slug = page.url | split: '/' | last -%}
{%- for group in site.data.nav -%}
{%- assign link = group.pages | first -%}
{%- assign link_slug = link.title | slugify -%}
{%- assign group_slug = group.title | slugify -%}
{%- assign active = nil -%}
{%- if page.group == group_slug -%}
{%- assign active = 'active' -%}
{%- endif -%}
{{ group.title }}
{%- for doc in group.pages -%}
{%- assign doc_slug = doc.title | slugify -%}
{%- assign active = nil -%}
{%- if page.group == group_slug and page_slug == doc_slug -%}
{%- assign active = 'active bd-sidenav-active' -%}
{%- endif -%}
{{ doc.title }}
{%- endfor -%}
{%- endfor -%}