diff --git a/_includes/components/children_nav.html b/_includes/components/children_nav.html
index bf380a1c..7d61de7e 100644
--- a/_includes/components/children_nav.html
+++ b/_includes/components/children_nav.html
@@ -1,50 +1,68 @@
 {%- comment -%}
-  Updated to support both `children` and `subcategories` for flexible YAML structures.
+  Include as: {%- include components/children_nav.html -%}
+  Depends on: page, site, nav_breadcrumbs.
+  Results in: HTML for the children-navigation component.
+  Includes: components/nav/sorted.html, toc_heading_custom.html.
+  Overwrites:
+    nav_ancestor_links, nav_top_node_titles, nav_child_candidates, nav_children,
+    nav_child, nav_child_ok, nav_child_ancestor, nav_sorted.
 {%- endcomment -%}
-
-{%- if page.has_children == false and page.subcategories == nil -%}
+{%- comment -%}
+  Whether a page has any children is checked efficiently by inspecting the cached
+  site_nav. If the page has no children, nav_children is set to an empty array;
+  otherwise nav_children is left unset. (The site_nav is rendered the first time
+  it is included, and that may overwrite various variables.)
+{%- endcomment -%}
+{%- if page.has_children == false -%}
   {%- assign nav_children = "" | split: "" -%}
 {%- else -%}
   {%- capture site_nav -%}
-    {%- include_cached components/site_nav.html all=true -%}
+  {%- include_cached components/site_nav.html all=true -%}
+  {%- endcapture -%}
+  {%- assign nav_children = nil -%}
+  {%- capture nav_list_link -%}
+  <a href="{{ page.url | relative_url }}" class="nav-list-link">
   {%- endcapture -%}
-
-  {%- assign nav_children = site_nav | where_exp: "item", "item.parent == page.url" | concat: page.subcategories -%}
+  {%- capture nav_list_simple -%}
+  <ul class="nav-list">
+  {%- endcapture -%}
+  {%- assign nav_child_start = site_nav
+        | split: nav_list_link | last
+        | split: "</a>" | slice: 1 | first -%}
+  {%- assign nav_child_test = nav_child_start
+        | remove_first: nav_list_simple | prepend: nav_list_simple -%}
+  {%- if nav_child_start != nav_child_test -%}
+    {%- assign nav_children = "" | split: "" -%}
+  {%- endif -%}
 {%- endif -%}
-
-{%- unless nav_children == empty -%}
-
+{%- unless nav_children -%}
+  {%- comment -%}
+    The layout is assumed to include components/breadcrumbs.html before this file,
+    otherwise it needs to be included here.
+  {%- endcomment -%}
   {%- assign nav_ancestors = "" | split: "" -%}
   {%- for nav_link in nav_breadcrumbs -%}
     {%- assign nav_title = nav_link | split: ">" | slice: 1 | first | append: ">" | remove: "</a>" -%}
     {%- assign nav_ancestors = nav_ancestors | push: nav_title -%}
   {%- endfor -%}
-
-  {%- assign nav_parenthood = site[page.collection] | default: site.html_pages | where_exp: "item", "item.title != nil" | group_by: "parent" -%}
-
-  {%- assign nav_top_nodes = nav_parenthood | where_exp: "item", "item.name == ''" | map: "items" | first -%}
-
-  {%- assign nav_top_node_titles = nav_top_nodes | map: "title" -%}
-
+  {%- assign nav_parenthood = site[page.collection] | default: site.html_pages
+    | where_exp: "item", "item.title != nil" | group_by: "parent" -%}
+  {%- assign nav_top_nodes = nav_parenthood
+      | where_exp: "item", "item.name == ''" | map: "items" | first -%}
+  {% assign nav_top_node_titles = nav_top_nodes | map: "title" -%}
   {%- include components/nav/children.html node=page ancestors=nav_ancestors all=true -%}
-
 {%- endunless -%}
-
 {%- if nav_children.size >= 1 -%}
-
   {%- if page.child_nav_order == 'desc' or page.child_nav_order == 'reversed' -%}
     {%- assign nav_children = nav_children | reverse -%}
   {%- endif -%}
-
 <hr>
 {% include toc_heading_custom.html %}
-
-<ul class="nav-list">
+<ul>
   {% for nav_child in nav_children %}
-    <li>
-      <a href="{{ nav_child.url | relative_url }}">{{ nav_child.title }}</a>
-    </li>
+  <li>
+    <a href="{{ nav_child.url | relative_url }}">{{ nav_child.title }}</a>{% if nav_child.summary %} - {{ nav_child.summary }}{% endif %}
+  </li>
   {% endfor %}
 </ul>
-
-{%- endif -%}
+{%- endif -%}
\ No newline at end of file
diff --git a/_includes/nav.html b/_includes/nav.html
index b7d47042..acd6bd7b 100644
--- a/_includes/nav.html
+++ b/_includes/nav.html
@@ -1,4 +1,3 @@
-{% macro render_nav(navlist) %}
 <ul class="nav-list">
   {% for nav in navlist %}
     {% assign has_children = nav.subcategories | default: nav.children %}
@@ -22,6 +21,3 @@
     </li>
   {% endfor %}
 </ul>
-{% endmacro %}
-
-{% render_nav navlist %}