diff --git a/frontend/src/components/layout/Sidebar.tsx b/frontend/src/components/layout/Sidebar.tsx
index d2eed210..6ee950d8 100644
--- a/frontend/src/components/layout/Sidebar.tsx
+++ b/frontend/src/components/layout/Sidebar.tsx
@@ -5,6 +5,7 @@ import {
   LayoutGrid, Clock, AlertTriangle, GitBranch, Layers, Code2, Wand2,
   ListChecks, Download, BarChart3, Rocket, BookOpen, MessageSquare,
   Settings, Pin, PinOff,
+  Zap, Database, HelpCircle,
 } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
@@ -62,6 +63,57 @@ export function Sidebar() {
 
   /* ── Navigation data ──────────────────────────────── */
 
+  /* ── Grouped nav: 5 top-level icons (Sentry-style) ── */
+
+  const railGroups: NavEntry[] = [
+    {
+      href: '/', icon: LayoutGrid, label: 'Home', shortLabel: 'Home',
+      matchPaths: ['/'],
+    },
+    {
+      href: '/sessions', icon: Zap, label: 'Work', shortLabel: 'Work',
+      badge: (stats?.active_count || 0) + (stats?.escalation_count || 0) || undefined,
+      matchPaths: ['/sessions', '/escalations', '/pilot'],
+      children: [
+        { href: '/sessions', label: 'Active Sessions', count: stats?.active_count || undefined },
+        { href: '/escalations', label: 'Escalations', count: stats?.escalation_count || undefined },
+      ],
+    },
+    {
+      href: '/trees', icon: Database, label: 'Knowledge', shortLabel: 'Know',
+      badge: stats?.tree_counts.total || undefined,
+      matchPaths: ['/trees', '/flows', '/my-trees', '/step-library', '/scripts', '/script-builder', '/review-queue'],
+      children: [
+        { href: '/trees', label: 'All Flows', count: stats?.tree_counts.total || undefined },
+        { href: '/trees?type=troubleshooting', label: 'Troubleshooting', count: stats?.tree_counts.troubleshooting || undefined },
+        { href: '/trees?type=procedural', label: 'Projects', count: stats?.tree_counts.procedural || undefined },
+        { href: '/trees?type=maintenance', label: 'Maintenance', count: stats?.tree_counts.maintenance || undefined },
+        { href: '/step-library', label: 'Step Library' },
+        { href: '/scripts', label: 'Scripts' },
+        { href: '/script-builder', label: 'Script Builder' },
+        { href: '/review-queue', label: 'Review Queue' },
+      ],
+    },
+    {
+      href: '/analytics', icon: BarChart3, label: 'Insights', shortLabel: 'Data',
+      matchPaths: ['/analytics', '/shares'],
+      children: [
+        { href: '/shares', label: 'Exports' },
+        { href: '/analytics', label: 'Analytics' },
+        { href: '/analytics/flowpilot', label: 'FlowPilot Analytics' },
+      ],
+    },
+    {
+      href: '/guides', icon: HelpCircle, label: 'Help', shortLabel: 'Help',
+      matchPaths: ['/guides', '/feedback'],
+      children: [
+        { href: '/guides', label: 'User Guides' },
+        { href: '/feedback', label: 'Feedback' },
+      ],
+    },
+  ]
+
+  /* Pinned mode still uses the detailed section layout */
   const sections: NavSection[] = [
     {
       title: 'RESOLVE',
@@ -102,8 +154,6 @@ export function Sidebar() {
   ]
 
   const footerItems: NavEntry[] = [
-    { href: '/guides', icon: BookOpen, label: 'User Guides', shortLabel: 'Guides' },
-    { href: '/feedback', icon: MessageSquare, label: 'Feedback', shortLabel: 'Feedbk' },
     { href: '/account', icon: Settings, label: 'Account', shortLabel: 'Acct' },
   ]
 
@@ -167,7 +217,7 @@ export function Sidebar() {
     return (
       <div
         key={key}
-        className="relative"
+        className="relative w-full"
         onMouseEnter={() => hasChildren && !sidebarPinned ? openFlyout(key) : undefined}
         onMouseLeave={() => hasChildren && !sidebarPinned ? closeFlyout() : undefined}
       >
@@ -378,30 +428,27 @@ export function Sidebar() {
     )
   }
 
-  /* Icon Rail (default) */
+  /* Icon Rail (default) — 5 grouped icons, Sentry-style */
   return (
     <nav
       ref={sidebarRef}
-      className="sidebar flex flex-col items-center"
-      style={{ background: '#0f1118', borderRight: '1px solid #1e2130' }}
+      className="sidebar flex flex-col items-center h-full"
+      style={{ background: '#0f1118', borderRight: '1px solid #1e2130', minHeight: '100vh' }}
       onWheel={handleWheel}
     >
-      {/* Nav sections */}
-      <div className="flex flex-col items-center w-full px-1.5 py-2 space-y-0.5">
-        {sections.map((section, si) => (
-          <div key={section.title} className="w-full">
-            {si > 0 && (
-              <div className="mx-3 my-2" style={{ borderTop: '1px solid #1e2130' }} />
-            )}
-            {section.items.map((item, ii) => renderRailItemWithRef(item, `${si}-${ii}`))}
+      {/* Grouped nav items */}
+      <div className="flex flex-col items-center w-full px-1.5 pt-3 space-y-1">
+        {railGroups.map((item, i) => (
+          <div key={`rail-${i}`} data-flyout-key={`rail-${i}`}>
+            {renderRailItem(item, `rail-${i}-inner`)}
           </div>
         ))}
       </div>
 
       <div className="flex-1" />
 
-      {/* Footer */}
-      <div className="flex flex-col items-center w-full px-1.5 py-2 space-y-0.5" style={{ borderTop: '1px solid #1e2130' }}>
+      {/* Footer: Account + Pin */}
+      <div className="flex flex-col items-center w-full px-1.5 pb-3 space-y-1" style={{ borderTop: '1px solid #1e2130' }}>
         {footerItems.map((item, i) => (
           <div key={`footer-${i}`} data-flyout-key={`footer-${i}`}>
             {renderRailItem(item, `footer-${i}-inner`)}