Allow only one category of external nav_links

_config.yml

@@ -28,13 +28,12 @@ search_enabled: true
 heading_anchors: true
 permalink: pretty
 nav_links:
-  Other:
-    Okpy:
-      - 'https://okpy.org'
-    Gradescope:
-      - 'https://gradescope.com'
-    Piazza:
-      - 'https://piazza.com'
+  Okpy:
+    - 'https://okpy.org'
+  Gradescope:
+    - 'https://gradescope.com'
+  Piazza:
+    - 'https://piazza.com'
 aux_links:
   'Kevin Lin':
     - 'https://kevinl.info'

_layouts/default.html

@@ -21,17 +21,15 @@ layout: table_wrappers
       <div class="navigation main-nav js-main-nav">
         {% include nav.html %}
         {% if site.nav_links != nil %}
+        <hr>
         <nav role="navigation" aria-label="Secondary navigation">
-          {% for category in site.nav_links %}
-          <h2 class="navigation-header">{{ category.first }}</h2>
           <ul class="navigation-list">
-            {% for link in category.last %}
+            {% for link in site.nav_links %}
             <li class="navigation-list-item">
               <a href="{{ link.last }}" class="navigation-list-link" target="_blank">{{ link.first }}</a>
             </li>
             {% endfor %}
           </ul>
-          {% endfor %}
         </nav>
         {% endif %}
       </div>

_sass/custom/custom.scss

@@ -8,5 +8,3 @@
 @import 'module';
 @import 'schedule';
 @import 'staffer';
-
-@import 'navigation';

_sass/custom/navigation.scss

-.navigation-header {
-  @extend .text-delta;
-}