diff --git a/CLAUDE.md b/CLAUDE.md
index ef042c7..1ba4a59 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -122,8 +122,7 @@ sort: 100           # controls nav ordering (lower = higher)
 section-id: blog    # assigns page to a nav section
 draft: true         # exclude from nav and search
 author: Name
-date: 2025-01-01
-datetime: 2025-01-01 13:00   # use this for posts (not `date` alone — see known limitations)
+created: 2025-01-01 13:00
 modified: 2025-01-15 09:00
 keywords: foo, bar
 description: Short description for search
@@ -153,13 +152,13 @@ Embed post lists in pages using fenced blocks:
 
 ````markdown
 ```mdcms
-posts-datetime-reversechronological
+posts-created-reversechronological
 limit: 10
 paginate: yes
 ```
 ````
 
-Reliable tags (others are known-broken): `posts-datetime-chronological-byyearmonth`, `posts-datetime-reversechronological`. Use `datetime` frontmatter (format: `YYYY-MM-DD HH:MM`) for posts — `date` alone does not work reliably.
+Reliable tags (others are known-broken): `posts-created-chronological-byyearmonth`, `posts-created-reversechronological`. Use `created` frontmatter (format: `YYYY-MM-DD HH:MM`) for posts.
 
 ## Release workflow
 
diff --git a/app/index.html b/app/index.html
index a80ba18..f8dff1a 100644
--- a/app/index.html
+++ b/app/index.html
@@ -371,6 +371,33 @@ body {
 }
 .topbar-nav .nav-item.active { border-left: none; background: var(--nav-active-bg); }
 
+/* ─── Topbar grouped navigation (dropdowns) ─── */
+.topbar-nav .nav-group { position: relative; }
+.topbar-nav .nav-trigger {
+  display: flex; align-items: center; gap: 0.25rem;
+  padding: 0.35rem 0.75rem; border-radius: 5px;
+  background: none; border: none; cursor: pointer;
+  color: var(--font-colour); font-size: 0.85rem;
+  font-family: inherit; white-space: nowrap; text-decoration: none; line-height: inherit;
+}
+.topbar-nav .nav-trigger:hover,
+.topbar-nav .nav-group.open > .nav-trigger { background: var(--nav-hover-bg); }
+.topbar-nav .nav-group.has-active > .nav-trigger { background: var(--nav-active-bg); }
+.topbar-nav .nav-caret { font-size: 0.6rem; color: var(--font-colour-muted); opacity: 0.55; line-height: 1; }
+.topbar-nav .nav-dropdown {
+  display: none; position: absolute; top: calc(100% + 4px); left: 0;
+  background: var(--bg-nav); border: 1px solid var(--divider);
+  border-radius: 6px; box-shadow: 0 4px 16px rgba(0,0,0,0.1);
+  min-width: 160px; z-index: 200; padding: 0.25rem 0;
+}
+.topbar-nav .nav-group.open > .nav-dropdown { display: block; }
+.topbar-nav .nav-dropdown .nav-item {
+  display: block; padding: 0.45rem 1rem;
+  border-left: none; border-radius: 0; white-space: nowrap;
+}
+.topbar-nav .nav-dropdown .nav-item:hover { background: var(--nav-hover-bg); }
+.topbar-nav .nav-dropdown .nav-item.active { background: var(--nav-active-bg); font-weight: 600; }
+
 .topbar-actions { display: flex; align-items: center; gap: 0.5rem; flex-shrink: 0; }
 
 .topbar-search { position: relative; }
@@ -732,6 +759,19 @@ body {
     border-left: none;
   }
   .layout-topbar .mobile-nav-panel .nav-item.active { border-left: none; font-weight: 600; }
+  .layout-topbar .mobile-nav-panel .nav-group-row { display: flex; align-items: stretch; }
+  .layout-topbar .mobile-nav-panel .nav-group-row .nav-item { flex: 1; }
+  .layout-topbar .mobile-nav-panel .nav-section-label {
+    flex: 1; display: flex; align-items: center;
+    padding: 0.6rem 1.25rem; font-size: 1rem; color: var(--font-colour); font-weight: 500;
+  }
+  .layout-topbar .mobile-nav-panel .nav-expand-btn {
+    background: none; border: none; cursor: pointer;
+    color: var(--font-colour-muted); padding: 0 1.25rem; font-size: 1.2rem; line-height: 1; flex-shrink: 0;
+  }
+  .layout-topbar .mobile-nav-panel .nav-group-children { display: none; }
+  .layout-topbar .mobile-nav-panel .nav-group-children.open { display: block; }
+  .layout-topbar .mobile-nav-panel .nav-group-children .nav-item { padding-left: 2.5rem; }
 }
 
 @media (max-width: 480px) {
@@ -1369,14 +1409,14 @@ function fmtDatetime(dtStr) {
 
   function parsePostTagName(name) {
     var m = name.match(
-      /^posts-(date|datetime)-(chronological|reversechronological)(?:-(byyear|byyearmonth|lastyear|lastmonth))?$/
+      /^posts-created-(chronological|reversechronological)(?:-(byyear|byyearmonth|lastyear|lastmonth))?$/
     );
     if (!m) return null;
-    return { field: m[1], order: m[2], modifier: m[3] || null };
+    return { order: m[1], modifier: m[2] || null };
   }
 
   function getPostEntries(parsed, options) {
-    const { field, order, modifier } = parsed;
+    const { order, modifier } = parsed;
 
     // Start with posts from search index
     let posts = (searchIndex || []).filter(function(e) {
@@ -1389,11 +1429,7 @@ function fmtDatetime(dtStr) {
     }
 
     // Field filter
-    if (field === 'datetime') {
-      posts = posts.filter(function(e) { return !!e.datetime; });
-    } else {
-      posts = posts.filter(function(e) { return !!e.date; });
-    }
+    posts = posts.filter(function(e) { return !!e.created; });
 
     // Time-window filter
     if (modifier === 'lastyear' || modifier === 'lastmonth') {
@@ -1402,15 +1438,13 @@ function fmtDatetime(dtStr) {
       if (modifier === 'lastyear') cutoff.setDate(cutoff.getDate() - 365);
       else cutoff.setDate(cutoff.getDate() - 30);
       posts = posts.filter(function(e) {
-        var raw = field === 'datetime' ? e.datetime.replace(' ', 'T') : e.date;
-        return new Date(raw) >= cutoff;
+        return new Date(e.created.replace(' ', 'T')) >= cutoff;
       });
     }
 
     // Sort
-    var sortKey = field === 'datetime' ? 'datetime' : 'date';
     posts.sort(function(a, b) {
-      var da = a[sortKey] || '', db = b[sortKey] || '';
+      var da = a.created || '', db = b.created || '';
       return order === 'chronological' ? da.localeCompare(db) : db.localeCompare(da);
     });
 
@@ -1523,7 +1557,6 @@ function fmtDatetime(dtStr) {
 
     var opts = tag.options;
     var posts = getPostEntries(parsed, opts);
-    var field = parsed.field;
     var modifier = parsed.modifier;
     var paginate = opts.paginate || 'no';
     var limitVal = opts.limit || 'all';
@@ -1532,7 +1565,7 @@ function fmtDatetime(dtStr) {
     // Format each entry
     var formatted = posts.map(function(p) {
       return {
-        display: field === 'datetime' ? fmtDatetime(p.datetime) : fmtDate(p.date),
+        display: fmtDatetime(p.created),
         title: p.title,
         file: p.file
       };
@@ -1565,12 +1598,10 @@ function fmtDatetime(dtStr) {
 
     // Grouped by year (or year+month)
     function getYear(p) {
-      var d = field === 'datetime' ? p.datetime : p.date;
-      return d ? d.substring(0, 4) : 'Unknown';
+      return p.created ? p.created.substring(0, 4) : 'Unknown';
     }
     function getYearMonth(p) {
-      var d = field === 'datetime' ? p.datetime : p.date;
-      return d ? d.substring(0, 7) : 'Unknown';
+      return p.created ? p.created.substring(0, 7) : 'Unknown';
     }
     function monthLabel(ym) {
       var m = parseInt(ym.substring(5, 7), 10);
@@ -1809,6 +1840,10 @@ function fmtDatetime(dtStr) {
       if (panel) panel.classList.remove('open');
       hamburger.innerHTML = ICONS.menu;
     };
+
+    document.addEventListener('click', () => {
+      document.querySelectorAll('.topbar-nav .nav-group.open').forEach(g => g.classList.remove('open'));
+    });
   }
 
   function buildSearchWidget() {
@@ -2109,18 +2144,141 @@ function fmtDatetime(dtStr) {
     tree.forEach(root => renderTreeSection(container, root, 0, groups));
   }
 
-  function renderFlat(container) {
-    // Topbar inline: pages only, sorted by global sort, draft-section pages excluded.
+  function buildTopbarNavItems() {
     const byCode = {};
     navSections.forEach(s => { if (s.code) byCode[s.code] = s; });
-    const visible = navData.filter(p => {
-      const sid = p['section-id'];
-      return !sid || !isDraftSection(sid, byCode);
+    const items = [];
+
+    // Sections (non-draft), each becomes a dropdown trigger
+    navSections.forEach(s => {
+      if (!s.code || isDraftSection(s.code, byCode)) return;
+      const pages = navData.filter(p => p['section-id'] === s.code && pageShouldDisplay(p));
+      pages.sort((a, b) => ((a.sort ?? 999) - (b.sort ?? 999)) || a.file.localeCompare(b.file));
+      if (!pages.length) return;
+      items.push({ type: 'section', sort: s.sort ?? 999, section: s, pages });
     });
-    visible.sort((a, b) => ((a.sort ?? 999) - (b.sort ?? 999)) || a.file.localeCompare(b.file));
-    visible.forEach(p => {
-      const item = makeNavItem(p, 0);
-      if (item) container.appendChild(item);
+
+    // Unsectioned pages (or pages whose section isn't in nav), grouped by sort century
+    const unsectioned = navData.filter(p => {
+      if (!pageShouldDisplay(p)) return false;
+      const sid = p['section-id'];
+      return !sid || !byCode[sid];
+    });
+    unsectioned.sort((a, b) => ((a.sort ?? 999) - (b.sort ?? 999)) || a.file.localeCompare(b.file));
+    const centuryMap = new Map();
+    unsectioned.forEach(p => {
+      const c = Math.floor((p.sort ?? 999) / 100);
+      if (!centuryMap.has(c)) centuryMap.set(c, []);
+      centuryMap.get(c).push(p);
+    });
+    for (const [, pgs] of centuryMap) {
+      items.push({ type: 'group', sort: pgs[0].sort ?? 999, primary: pgs[0], children: pgs.slice(1) });
+    }
+
+    items.sort((a, b) => a.sort - b.sort);
+    return items;
+  }
+
+  function makeTopbarPageGroup({ primary, children }, isMobile) {
+    const group = el('div', { className: 'nav-group' });
+    const hasChildren = children.length > 0;
+
+    if (isMobile) {
+      const row = el('div', { className: 'nav-group-row' });
+      const link = makeNavItem(primary, 0);
+      if (link) row.appendChild(link);
+      if (hasChildren) {
+        const childrenEl = el('div', { className: 'nav-group-children' });
+        children.forEach(p => { const it = makeNavItem(p, 1); if (it) childrenEl.appendChild(it); });
+        const btn = el('button', { className: 'nav-expand-btn', 'aria-label': 'Expand', textContent: '+' });
+        btn.addEventListener('click', () => {
+          const open = childrenEl.classList.toggle('open');
+          btn.textContent = open ? '−' : '+';
+        });
+        row.appendChild(btn);
+        group.appendChild(row);
+        group.appendChild(childrenEl);
+      } else {
+        group.appendChild(row);
+      }
+    } else {
+      const title = pageDisplayTitle(primary);
+      const trigger = el('a', { className: 'nav-trigger', href: '#' + primary.file, 'data-file': primary.file });
+      trigger.appendChild(el('span', { textContent: title }));
+      if (hasChildren) trigger.appendChild(el('span', { className: 'nav-caret', textContent: '▾' }));
+      group.appendChild(trigger);
+
+      if (hasChildren) {
+        const dropdown = el('div', { className: 'nav-dropdown' });
+        children.forEach(p => { const it = makeNavItem(p, 0); if (it) dropdown.appendChild(it); });
+        group.appendChild(dropdown);
+        group.addEventListener('mouseenter', () => group.classList.add('open'));
+        group.addEventListener('mouseleave', () => group.classList.remove('open'));
+        trigger.addEventListener('click', e => {
+          e.preventDefault();
+          e.stopPropagation();
+          group.classList.toggle('open');
+          navigateTo(primary.file);
+          if (window._closeMobileMenu) window._closeMobileMenu();
+        });
+      } else {
+        trigger.addEventListener('click', e => {
+          e.preventDefault();
+          navigateTo(primary.file);
+          if (window._closeMobileMenu) window._closeMobileMenu();
+        });
+      }
+    }
+
+    return group;
+  }
+
+  function makeTopbarSection({ section, pages }, isMobile) {
+    const group = el('div', { className: 'nav-group' });
+    const isHidden = section.pagesvisibility === 'hidden';
+    const name = sectionDisplayName(section);
+
+    if (isMobile) {
+      const row = el('div', { className: 'nav-group-row' });
+      row.appendChild(el('span', { className: 'nav-section-label', textContent: name }));
+      const childrenEl = el('div', { className: 'nav-group-children' + (isHidden ? '' : ' open') });
+      pages.forEach(p => { const it = makeNavItem(p, 1); if (it) childrenEl.appendChild(it); });
+      const btn = el('button', { className: 'nav-expand-btn', 'aria-label': 'Expand', textContent: isHidden ? '+' : '−' });
+      btn.addEventListener('click', () => {
+        const open = childrenEl.classList.toggle('open');
+        btn.textContent = open ? '−' : '+';
+      });
+      row.appendChild(btn);
+      group.appendChild(row);
+      group.appendChild(childrenEl);
+    } else {
+      const trigger = el('button', { className: 'nav-trigger', type: 'button' });
+      trigger.appendChild(el('span', { textContent: name }));
+      trigger.appendChild(el('span', { className: 'nav-caret', textContent: '▾' }));
+      trigger.addEventListener('click', e => { e.stopPropagation(); group.classList.toggle('open'); });
+      group.appendChild(trigger);
+
+      const dropdown = el('div', { className: 'nav-dropdown' });
+      pages.forEach(p => { const it = makeNavItem(p, 0); if (it) dropdown.appendChild(it); });
+      group.appendChild(dropdown);
+
+      if (!isHidden) {
+        group.addEventListener('mouseenter', () => group.classList.add('open'));
+        group.addEventListener('mouseleave', () => group.classList.remove('open'));
+      }
+    }
+
+    return group;
+  }
+
+  function renderTopbarGrouped(container, isMobile) {
+    const items = buildTopbarNavItems();
+    items.forEach(item => {
+      container.appendChild(
+        item.type === 'group'
+          ? makeTopbarPageGroup(item, isMobile)
+          : makeTopbarSection(item, isMobile)
+      );
     });
   }
 
@@ -2130,19 +2288,23 @@ function fmtDatetime(dtStr) {
     const mobile = document.getElementById('mobileNavLinks');
     if (main) {
       main.innerHTML = '';
-      if (topbar) renderFlat(main);
+      if (topbar) renderTopbarGrouped(main, false);
       else renderTree(main);
     }
     if (mobile) {
       mobile.innerHTML = '';
-      renderTree(mobile);
+      if (topbar) renderTopbarGrouped(mobile, true);
+      else renderTree(mobile);
     }
   }
 
   function highlightNav(file) {
-    document.querySelectorAll('.nav-item').forEach(item => {
+    document.querySelectorAll('.nav-item, .nav-trigger[data-file]').forEach(item => {
       item.classList.toggle('active', item.getAttribute('data-file') === file);
     });
+    document.querySelectorAll('.topbar-nav .nav-group').forEach(group => {
+      group.classList.toggle('has-active', !!group.querySelector('[data-file].active'));
+    });
   }
 
   // ─── Page loading ─────────────────────────────────────────
@@ -2189,12 +2351,12 @@ function fmtDatetime(dtStr) {
     hydrateMdcmsTags();
 
     const firstH = contentEl.querySelector('.md-content h1, .md-content h2');
-    if (firstH && (meta.author || meta.created || meta.date || meta.datetime)) {
+    if (firstH && (meta.author || meta.created)) {
       const metaEl = document.createElement('div');
       metaEl.className = 'page-meta';
       let metaText = '';
       if (meta.author) metaText += meta.author;
-      const displayDate = meta.datetime || meta.date || meta.created;
+      const displayDate = meta.created;
       if (displayDate) {
         if (metaText) metaText += ' | ';
         metaText += 'Published ' + formatDate(displayDate);
diff --git a/app/pages/home.md b/app/pages/home.md
index 5b41f1f..ccf41dc 100644
--- a/app/pages/home.md
+++ b/app/pages/home.md
@@ -18,7 +18,7 @@ If you want to test `MD-CMS` you can grab `samplesite` from the repo and place t
 ## Reverse chronological (newest first)
 
 ```mdcms
-posts-date-reversechronological
+posts-created-reversechronological
 limit: 3
 paginate: no
 ```
@@ -26,25 +26,25 @@ paginate: no
 ## Chronological (oldest first)
 
 ```mdcms
-posts-date-chronological
+posts-created-chronological
 limit: all
 paginate: none
 ```
 
-## By year (date, reverse chrono)
+## By year (reverse chrono)
 
 ```mdcms
-posts-date-reversechronological-byyear
+posts-created-reversechronological-byyear
 limit: all
 defaultyear: current
 selectyear: yes
 paginate: none
 ```
 
-## By year+month (datetime, chrono)
+## By year+month (chrono)
 
 ```mdcms
-posts-datetime-chronological-byyearmonth
+posts-created-chronological-byyearmonth
 limit: all
 defaultyear: 2024
 selectyear: yes
@@ -53,7 +53,7 @@ selectyear: yes
 ## Last 30 days
 
 ```mdcms
-posts-date-reversechronological-lastmonth
+posts-created-reversechronological-lastmonth
 limit: all
 paginate: none
 ```
@@ -61,7 +61,7 @@ paginate: none
 ## Paginated (2 per page)
 
 ```mdcms
-posts-datetime-reversechronological
+posts-created-reversechronological
 limit: 2
 paginate: yes
 ```
diff --git a/mdcms.py b/mdcms.py
index ee7cf84..5a7ad57 100644
--- a/mdcms.py
+++ b/mdcms.py
@@ -175,8 +175,6 @@ def scan_and_categorize(directory: Path, site_root: Path, known_codes: set) -> l
                 "sort": meta.get("sort"),
                 "section-id": meta.get("section-id"),
                 "author": meta.get("author"),
-                "date": str(meta.get("date", "")),
-                "datetime": str(meta.get("datetime", "")),
                 "created": str(meta.get("created", "")),
                 "modified": str(meta.get("modified", "")),
                 "language": meta.get("language", "en"),
@@ -328,8 +326,8 @@ def generate_search_json(
             "keywords": r.get("keywords", ""),
             "description": r.get("description", ""),
             "author": r.get("author"),
-            "date": r.get("date", ""),
-            "datetime": r.get("datetime", ""),
+            "created": r.get("created", ""),
+            "modified": r.get("modified", ""),
             "language": r.get("language", "en"),
             "body": r.get("body", ""),
         }
diff --git a/samplesite/pages/blog.md b/samplesite/pages/blog.md
index e43716e..dc1b4ad 100644
--- a/samplesite/pages/blog.md
+++ b/samplesite/pages/blog.md
@@ -11,7 +11,7 @@ Stay up to date with announcements, product updates, and industry insights from
 ## All Posts
 
 ```mdcms
-posts-date-reversechronological-byyear
+posts-created-reversechronological-byyear
 limit: all
 defaultyear: current
 selectyear: yes
diff --git a/samplesite/pages/blog.nb.md b/samplesite/pages/blog.nb.md
index 23c1f01..5962716 100644
--- a/samplesite/pages/blog.nb.md
+++ b/samplesite/pages/blog.nb.md
@@ -11,7 +11,7 @@ Bli oppdatert med kunngjøringer, produktoppdateringer og bransjeinnsikter fra A
 ## Alle innlegg
 
 ```mdcms
-posts-date-reversechronological-byyear
+posts-created-reversechronological-byyear
 limit: all
 defaultyear: current
 selectyear: yes
diff --git a/samplesite/posts/2022-q4-report.md b/samplesite/posts/2022-q4-report.md
index c24a474..37cf475 100644
--- a/samplesite/posts/2022-q4-report.md
+++ b/samplesite/posts/2022-q4-report.md
@@ -1,7 +1,6 @@
 ---
 title: Q4 2022 Performance Report
-date: 2022-11-15
-datetime: 2022-11-15 09:00
+created: 2022-11-15 09:00
 author: Sarah Chen
 ---
 
diff --git a/samplesite/posts/2023-analytics-launch.md b/samplesite/posts/2023-analytics-launch.md
index 96dd7d6..264e94a 100644
--- a/samplesite/posts/2023-analytics-launch.md
+++ b/samplesite/posts/2023-analytics-launch.md
@@ -1,7 +1,6 @@
 ---
 title: Introducing Advanced Analytics Dashboard
-date: 2023-03-22
-datetime: 2023-03-22 14:30
+created: 2023-03-22 14:30
 author: David Okonkwo
 ---
 
diff --git a/samplesite/posts/2023-security-update.md b/samplesite/posts/2023-security-update.md
index 32e5169..e6046f4 100644
--- a/samplesite/posts/2023-security-update.md
+++ b/samplesite/posts/2023-security-update.md
@@ -1,7 +1,6 @@
 ---
 title: Security Update - November 2023
-date: 2023-11-10
-datetime: 2023-11-10 11:45
+created: 2023-11-10 11:45
 author: Security Team
 ---
 
diff --git a/samplesite/posts/2024-roadmap.md b/samplesite/posts/2024-roadmap.md
index b082033..1f0997e 100644
--- a/samplesite/posts/2024-roadmap.md
+++ b/samplesite/posts/2024-roadmap.md
@@ -1,7 +1,6 @@
 ---
 title: 2024 Product Roadmap
-date: 2024-01-30
-datetime: 2024-01-30 10:00
+created: 2024-01-30 10:00
 author: David Okonkwo
 ---
 
diff --git a/samplesite/posts/2024-success-stories.md b/samplesite/posts/2024-success-stories.md
index 69be3fb..16a46bd 100644
--- a/samplesite/posts/2024-success-stories.md
+++ b/samplesite/posts/2024-success-stories.md
@@ -1,7 +1,6 @@
 ---
 title: Q2 2024 Customer Success Stories
-date: 2024-07-08
-datetime: 2024-07-08 15:20
+created: 2024-07-08 15:20
 author: Maria Garcia
 ---
 
diff --git a/samplesite/posts/2026-v9-release.md b/samplesite/posts/2026-v9-release.md
index 63dfec1..20f37d5 100644
--- a/samplesite/posts/2026-v9-release.md
+++ b/samplesite/posts/2026-v9-release.md
@@ -1,7 +1,6 @@
 ---
 title: Version 9.0 Released — A New Era
-date: 2026-04-10
-datetime: 2026-04-10 13:00
+created: 2026-04-10 13:00
 author: Sarah Chen
 ---