diff --git a/.github/workflows/deploy_website.yml b/.github/workflows/deploy_website.yml
index 18ce205b0bc655d805bac0a4a4df7ddb18a0087f..268b30cb3bff8427a1e9c0958df2ac1774b765ee 100644
--- a/.github/workflows/deploy_website.yml
+++ b/.github/workflows/deploy_website.yml
@@ -11,7 +11,7 @@ jobs:
       - uses: actions/setup-python@v2
         with:
           python-version: 3.x
-      - run: pip install mkdocs-material
+      - run: pip install mkdocs-material==9.0.3
       - run: pip install https://github.com/mitya57/python-markdown-math/archive/master.zip
       - run: pip install mkdocs-exclude
       - run: pip install mkdocs-redirects
diff --git a/doc/custom.css b/doc/custom.css
index cd5919e2730e192cac67d9937819ba22f13bc0f0..f36d4b4f5e843e37b77702c92dc7c15aa1831d20 100644
--- a/doc/custom.css
+++ b/doc/custom.css
@@ -60,4 +60,4 @@
         -ms-scroll-snap-type: none;
         scroll-snap-type: none;
     }
-}
\ No newline at end of file
+}
diff --git a/mkdocs.yml b/mkdocs.yml
index 19517c35c38404f7369b34d3fbfeb82fa3fe9b35..a630d3d01df2e3b4128b9dabe75273b5383da5c6 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -15,7 +15,7 @@ theme:
 docs_dir: 'doc'
 extra_css:
     - custom.css
-    - https://combinatronics.com/maths/moodle-qtype_stack/master/styles.css
+    - 'https://cdn.jsdelivr.net/gh/maths/moodle-qtype_stack@master/styles.css'
 markdown_extensions:
     - mdx_math
     - extra
diff --git a/site_overrides/main.html b/site_overrides/main.html
index 93c0e756595675b98bb980026bafc2bf7e3462e1..f7af3d083cf5050bc9e9a94d2bc5cdcf4b4fe349 100644
--- a/site_overrides/main.html
+++ b/site_overrides/main.html
@@ -13,7 +13,7 @@
   </script>
 {% endblock %}
 
-<!--Override basic header-->
+ <!--Override basic header -->
 {% block header %}
 <header class="md-header" data-md-component="header">
   <nav class="md-header__inner md-grid" aria-label="{{ lang.t('header.title') }}">
@@ -24,13 +24,13 @@
     <label class="md-header__button md-icon" for="__drawer">
       {% include ".icons/material/menu" ~ ".svg" %}
     </label>
-    <!--Make site title permament-->
+    <!--Make site title permament -->
     <div class="md-header__title" data-md-component="header-title">
-      <div class="md-header__ellipsis md-header__topic md-ellipsis">
-        {{ config.site_name }}
+      <div class="md-header__ellipsis md-ellipsis">
+        <b>{{ config.site_name }}</b>
       </div>
     </div>
-     {% if "search" in config["plugins"] %}
+     {% if "material/search" in config.plugins %}
       <label class="md-header__button md-icon" for="__search">
         {% include ".icons/material/magnify.svg" %}
       </label>
diff --git a/site_overrides/partials/nav-item.html b/site_overrides/partials/nav-item.html
index c6896fb35e4af952f56f0d1feaf3693b3cbfbd06..45c66cd29bdff4832bc9dc533ae50cf22adc2b89 100644
--- a/site_overrides/partials/nav-item.html
+++ b/site_overrides/partials/nav-item.html
@@ -3,7 +3,6 @@
   {% if nav_item.active %}
     {% set class = class ~ " md-nav__item--active" %}
   {% endif %}
-
 <!--Skip first level in the navigation bar, i.e. the "En" level-->
   {%if nav_item.title == "En"%}
     {% set base = path %}
@@ -20,17 +19,39 @@
       {% set class = class ~ " md-nav__item--section" %}
     {% endif %}
     <li class="{{ class }} md-nav__item--nested">
+      {% set expanded = "navigation.expand" in features %}
+      {% set active = nav_item.active or expanded %}
       {% set checked = "checked" if nav_item.active %}
-      {% if "navigation.expand" in features and not checked %}
-        <input class="md-nav__toggle md-toggle" data-md-toggle="{{ path }}"
-        data-md-state="indeterminate" type="checkbox" id="{{ path }}" checked>
+      {% if expanded and not checked %}
+        {% set indeterminate = "md-toggle--indeterminate" %}
+      {% endif %}
+      <input class="md-nav__toggle md-toggle {{ indeterminate }}" data-md-toggle="{{ path }}" 
+      type="checkbox" id="{{ path }}" {{ checked }}>
+      {% set indexes = [] %}
+      {% if "navigation.indexes" in features %}
+        {% for nav_item in nav_item.children %}
+          {% if nav_item.is_index and not index is defined %}
+            {% set _ = indexes.append(nav_item) %}
+          {% endif %}
+        {% endfor %}
+      {% endif %}
+      {% if not indexes %}
+        <label class="md-nav__link" for="{{ path }}" tabindex="0" aria-expanded="{{ nav_item.active | tojson }}">
+          {{ nav_item.title }}
+          <span class="md-nav__icon md-icon"></span>
+        </label>
       {% else %}
-        <input class="md-nav__toggle md-toggle" data-md-toggle="{{ path }}" type="checkbox" id="{{ path }}" {{ checked }}>
+        {% set index = indexes | first %}
+        {% set class = "md-nav__link--active" if index == page %}
+        <div class="md-nav__link md-nav__link--index {{ class }}">
+          <a href="{{ index.url | url }}">{{ nav_item.title }}</a>
+          {% if nav_item.children | length > 1 %}
+            <label for="{{ path }}">
+              <span class="md-nav__icon md-icon"></span>
+            </label>
+          {% endif %}
+        </div>
       {% endif %}
-      <label class="md-nav__link" for="{{ path }}">
-        {{ nav_item.title }}
-        <span class="md-nav__icon md-icon"></span>
-      </label>
       <nav class="md-nav" aria-label="{{ nav_item.title }}" data-md-level="{{ level }}">
         <label class="md-nav__title" for="{{ path }}">
           <span class="md-nav__icon md-icon"></span>
@@ -38,7 +59,9 @@
         </label>
         <ul class="md-nav__list" data-md-scrollfix>
           {% for nav_item in nav_item.children %}
-            {{ render(nav_item, path ~ "_" ~ loop.index, level + 1) }}
+            {% if not indexes or nav_item != indexes | first %}
+              {{ render(nav_item, path ~ "_" ~ loop.index, level + 1) }}
+            {% endif %}
           {% endfor %}
         </ul>
       </nav>