diff --git a/frontend/src/components/common/BrandLogo.tsx b/frontend/src/components/common/BrandLogo.tsx
index 9b952c9b..83e287a1 100644
--- a/frontend/src/components/common/BrandLogo.tsx
+++ b/frontend/src/components/common/BrandLogo.tsx
@@ -5,37 +5,36 @@ interface BrandLogoProps {
   className?: string
 }
 
+/**
+ * Brand logo mark: gradient cyan square with rounded corners
+ * containing a white lightning bolt.
+ */
 export function BrandLogo({ size = 'sm', className }: BrandLogoProps) {
-  const sizeClasses = size === 'sm' ? 'h-8 w-8' : 'h-20 w-20'
-  const strokeBase = size === 'sm' ? 1 : 2
-  const strokeThick = size === 'sm' ? 1.25 : 2.5
-  const dashArray = size === 'sm' ? '1 1.5' : '2 3'
-  const nodeR = size === 'sm' ? { outer: 2.5, inner: 2.75 } : { outer: 5, inner: 5.5 }
-  const hubR = size === 'sm' ? { glow: 5, solid: 3.5 } : { glow: 10, solid: 7 }
-  const vb = size === 'sm' ? '0 0 40 40' : '0 0 80 80'
-  const s = size === 'sm' ? 1 : 2
-  const gradId = size === 'sm' ? 'logoGradSm' : 'logoGradLg'
-  const gradEnd = String(40 * (size === 'sm' ? 1 : 2))
+  const dim = size === 'sm' ? 30 : 64
 
   return (
-    <svg viewBox={vb} fill="none" className={cn(sizeClasses, className)}>
-      <defs>
-        <linearGradient id={gradId} x1="0" y1="0" x2={gradEnd} y2={gradEnd} gradientUnits="userSpaceOnUse">
-          <stop offset="0%" stopColor="#06b6d4" />
-          <stop offset="100%" stopColor="#22d3ee" />
-        </linearGradient>
-      </defs>
-      <circle cx={5 * s} cy={7 * s} r={nodeR.outer} fill={`url(#${gradId})`} opacity="0.5" />
-      <circle cx={5 * s} cy={15 * s} r={nodeR.inner} fill={`url(#${gradId})`} opacity="0.7" />
-      <circle cx={5 * s} cy={25 * s} r={nodeR.inner} fill={`url(#${gradId})`} opacity="0.7" />
-      <circle cx={5 * s} cy={33 * s} r={nodeR.outer} fill={`url(#${gradId})`} opacity="0.5" />
-      <path d={`M${7.5 * s} ${7 * s}L${14 * s} ${17 * s}`} stroke={`url(#${gradId})`} strokeWidth={strokeBase} strokeLinecap="round" strokeDasharray={dashArray} opacity="0.4" />
-      <path d={`M${7.75 * s} ${15 * s}L${14 * s} ${19 * s}`} stroke={`url(#${gradId})`} strokeWidth={strokeBase} strokeLinecap="round" opacity="0.5" />
-      <path d={`M${7.75 * s} ${25 * s}L${14 * s} ${21 * s}`} stroke={`url(#${gradId})`} strokeWidth={strokeBase} strokeLinecap="round" opacity="0.5" />
-      <path d={`M${7.5 * s} ${33 * s}L${14 * s} ${23 * s}`} stroke={`url(#${gradId})`} strokeWidth={strokeBase} strokeLinecap="round" strokeDasharray={dashArray} opacity="0.4" />
-      <circle cx={18 * s} cy={20 * s} r={hubR.glow} fill={`url(#${gradId})`} opacity="0.15" />
-      <circle cx={18 * s} cy={20 * s} r={hubR.solid} fill={`url(#${gradId})`} opacity="0.9" />
-      <path d={`M${21.5 * s} ${20 * s}H${35 * s}M${35 * s} ${20 * s}L${30 * s} ${15 * s}M${35 * s} ${20 * s}L${30 * s} ${25 * s}`} stroke={`url(#${gradId})`} strokeWidth={strokeThick} strokeLinecap="round" strokeLinejoin="round" />
-    </svg>
+    <div
+      className={cn('shrink-0 flex items-center justify-center', className)}
+      style={{
+        width: dim,
+        height: dim,
+        borderRadius: size === 'sm' ? 8 : 14,
+        background: 'linear-gradient(135deg, #06b6d4, #22d3ee)',
+      }}
+    >
+      <svg
+        viewBox="0 0 24 24"
+        fill="none"
+        style={{ width: dim * 0.5, height: dim * 0.5 }}
+      >
+        <path
+          d="M13 2L4.5 13.5H12L11 22L19.5 10.5H12L13 2Z"
+          fill="white"
+          stroke="white"
+          strokeWidth="0.5"
+          strokeLinejoin="round"
+        />
+      </svg>
+    </div>
   )
 }
diff --git a/frontend/src/components/common/BrandWordmark.tsx b/frontend/src/components/common/BrandWordmark.tsx
index bd0e9318..a5eadf82 100644
--- a/frontend/src/components/common/BrandWordmark.tsx
+++ b/frontend/src/components/common/BrandWordmark.tsx
@@ -9,13 +9,12 @@ export function BrandWordmark({ size = 'sm', className }: BrandWordmarkProps) {
   return (
     <span
       className={cn(
-        'font-heading font-bold tracking-tight',
+        'font-heading font-bold tracking-tight text-[#f0f2f5]',
         size === 'sm' ? 'text-xl' : 'text-3xl',
         className
       )}
     >
-      <span className="text-foreground">Resolution</span>
-      <span className="text-gradient-brand">Flow</span>
+      ResolutionFlow
     </span>
   )
 }
diff --git a/frontend/src/components/layout/AppLayout.tsx b/frontend/src/components/layout/AppLayout.tsx
index cc870ab0..d9ea115f 100644
--- a/frontend/src/components/layout/AppLayout.tsx
+++ b/frontend/src/components/layout/AppLayout.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useState, useCallback } from 'react'
 import { useLocation, useNavigate, Link } from 'react-router-dom'
-import { Menu, X, LayoutGrid, Clock, Network, AlertTriangle, Code2, Wand2, BarChart3, Settings, LogOut, Shield, Library } from 'lucide-react'
+import { Menu, X, LayoutGrid, Clock, AlertTriangle, GitBranch, Code2, Wand2, BarChart3, Settings, LogOut, Shield, Layers } from 'lucide-react'
 import { useAuthStore } from '@/store/authStore'
 import { usePermissions } from '@/hooks/usePermissions'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
@@ -16,7 +16,7 @@ export function AppLayout() {
   const navigate = useNavigate()
   const { user, logout } = useAuthStore()
   const { effectiveRole } = usePermissions()
-  const sidebarCollapsed = useUserPreferencesStore(s => s.sidebarCollapsed)
+  const sidebarPinned = useUserPreferencesStore(s => s.sidebarPinned)
   const [mobileMenuOpen, setMobileMenuOpen] = useState(false)
 
   // Close mobile menu on route change
@@ -54,8 +54,8 @@ export function AppLayout() {
     { path: '/', label: 'Dashboard', icon: LayoutGrid },
     { path: '/sessions', label: 'Active Sessions', icon: Clock },
     { path: '/escalations', label: 'Escalations', icon: AlertTriangle },
-    { path: '/trees', label: 'Flows', icon: Network },
-    { path: '/step-library', label: 'Step Library', icon: Library },
+    { path: '/trees', label: 'Flows', icon: GitBranch },
+    { path: '/step-library', label: 'Step Library', icon: Layers },
     { path: '/scripts', label: 'Scripts', icon: Code2 },
     { path: '/script-builder', label: 'Script Builder', icon: Wand2 },
     { path: '/analytics', label: 'Analytics', icon: BarChart3 },
@@ -64,34 +64,8 @@ export function AppLayout() {
 
   return (
     <>
-      {/* Atmosphere orbs — ambient light behind glass */}
       <div
-        className="pointer-events-none fixed z-0"
-        style={{
-          top: '-120px',
-          right: '-80px',
-          width: '600px',
-          height: '600px',
-          borderRadius: '50%',
-          background: 'radial-gradient(circle, rgba(6, 182, 212, 0.15) 0%, rgba(6, 182, 212, 0.04) 40%, transparent 70%)',
-          filter: 'blur(60px)',
-        }}
-      />
-      <div
-        className="pointer-events-none fixed z-0"
-        style={{
-          bottom: '-100px',
-          left: '-60px',
-          width: '500px',
-          height: '500px',
-          borderRadius: '50%',
-          background: 'radial-gradient(circle, rgba(99, 102, 241, 0.08) 0%, rgba(99, 102, 241, 0.02) 40%, transparent 70%)',
-          filter: 'blur(50px)',
-        }}
-      />
-
-      <div
-        className={cn('app-shell relative z-1', sidebarCollapsed && 'app-shell--collapsed')}
+        className={cn('app-shell relative z-1', sidebarPinned && 'app-shell--pinned')}
         data-testid="app-shell"
       >
       {/* Top Bar - spans full width */}
@@ -104,8 +78,9 @@ export function AppLayout() {
 
       {/* Mobile hamburger - overlaid on topbar */}
       <button
+        type="button"
         onClick={() => setMobileMenuOpen(true)}
-        className="fixed left-4 top-3.5 z-50 rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground transition-colors md:hidden"
+        className="fixed left-4 top-3.5 z-50 rounded-lg p-2 text-[#848b9b] hover:bg-[#14161d] hover:text-[#e2e5eb] transition-colors md:hidden"
         aria-label="Open menu"
       >
         <Menu size={20} />
@@ -119,17 +94,19 @@ export function AppLayout() {
             onClick={() => setMobileMenuOpen(false)}
             aria-hidden="true"
           />
-          <nav className="absolute inset-y-0 left-0 w-72 border-r border-border bg-[var(--sidebar-bg)] shadow-2xl animate-slide-in-left">
-            <div className="flex h-14 items-center justify-between border-b border-border px-4">
+          <nav
+            className="absolute inset-y-0 left-0 w-72 shadow-2xl animate-slide-in-left"
+            style={{ background: '#0f1118', borderRight: '1px solid #1e2130' }}
+          >
+            <div className="flex h-14 items-center justify-between px-4" style={{ borderBottom: '1px solid #1e2130' }}>
               <Link to="/" className="flex items-center gap-2.5">
-                <div className="flex h-8 w-8 items-center justify-center rounded-lg bg-gradient-brand">
-                  <BrandLogo size="sm" className="h-4 w-4" />
-                </div>
-                <span className="text-sm font-heading font-bold">ResolutionFlow</span>
+                <BrandLogo size="sm" />
+                <span className="text-sm font-heading font-bold text-[#f0f2f5]">ResolutionFlow</span>
               </Link>
               <button
+                type="button"
                 onClick={() => setMobileMenuOpen(false)}
-                className="rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground"
+                className="rounded-lg p-2 text-[#848b9b] hover:bg-[#14161d] hover:text-[#e2e5eb]"
                 aria-label="Close menu"
               >
                 <X size={18} />
@@ -138,10 +115,10 @@ export function AppLayout() {
 
             <div className="flex flex-col p-3">
               {/* User info */}
-              <div className="mb-3 border-b border-border pb-3 px-3">
-                <p className="text-sm font-medium text-foreground">{user?.name || user?.email}</p>
+              <div className="mb-3 pb-3 px-3" style={{ borderBottom: '1px solid #1e2130' }}>
+                <p className="text-sm font-medium text-[#e2e5eb]">{user?.name || user?.email}</p>
                 {effectiveRole && effectiveRole !== 'engineer' && (
-                  <span className="mt-1 inline-flex items-center gap-1 text-xs text-muted-foreground">
+                  <span className="mt-1 inline-flex items-center gap-1 text-xs text-[#848b9b]">
                     <Shield size={10} />
                     {effectiveRole === 'super_admin' ? 'Super Admin' : effectiveRole === 'owner' ? 'Owner' : 'Viewer'}
                   </span>
@@ -162,8 +139,8 @@ export function AppLayout() {
                       className={cn(
                         'flex items-center gap-3 rounded-lg px-3 py-2.5 text-sm font-medium transition-colors',
                         isActive
-                          ? 'bg-[var(--sidebar-active)] text-foreground'
-                          : 'text-muted-foreground hover:bg-[var(--sidebar-hover)] hover:text-foreground'
+                          ? 'bg-[rgba(34,211,238,0.10)] text-[#e2e5eb]'
+                          : 'text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]'
                       )}
                     >
                       <Icon size={18} />
@@ -174,10 +151,11 @@ export function AppLayout() {
               </div>
 
               {/* Logout */}
-              <div className="mt-3 border-t border-border pt-3">
+              <div className="mt-3 pt-3" style={{ borderTop: '1px solid #1e2130' }}>
                 <button
+                  type="button"
                   onClick={handleLogout}
-                  className="flex w-full items-center gap-3 rounded-lg px-3 py-2.5 text-sm font-medium text-muted-foreground hover:bg-[var(--sidebar-hover)] hover:text-foreground transition-colors"
+                  className="flex w-full items-center gap-3 rounded-lg px-3 py-2.5 text-sm font-medium text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb] transition-colors"
                 >
                   <LogOut size={18} />
                   Logout
diff --git a/frontend/src/components/layout/Sidebar.tsx b/frontend/src/components/layout/Sidebar.tsx
index 796034f7..d2eed210 100644
--- a/frontend/src/components/layout/Sidebar.tsx
+++ b/frontend/src/components/layout/Sidebar.tsx
@@ -1,173 +1,420 @@
-import { useCallback, useEffect, useState } from 'react'
-import { useLocation } from 'react-router-dom'
+import { useCallback, useEffect, useRef, useState } from 'react'
+import { Link, useLocation } from 'react-router-dom'
+import type { LucideIcon } from 'lucide-react'
 import {
-  LayoutGrid, Network, Clock, FileOutput, BarChart3, TrendingUp,
-  Settings, PanelLeftClose, PanelLeftOpen, MessageSquareText, ListChecks,
-  BookOpen, Code2, Library, AlertTriangle, Wand2,
+  LayoutGrid, Clock, AlertTriangle, GitBranch, Layers, Code2, Wand2,
+  ListChecks, Download, BarChart3, Rocket, BookOpen, MessageSquare,
+  Settings, Pin, PinOff,
 } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
 import { sidebarApi } from '@/api'
 import type { SidebarStatsResponse } from '@/api/sidebar'
-import { NavItem } from './NavItem'
+import { prefetchForRoute } from '@/lib/routePrefetch'
 
-// Semantic icon colors — each nav item gets a unique color for visual landmarks
-const NAV_COLORS = {
-  dashboard: '#22d3ee',  // cyan-400
-  flows:     '#a78bfa',  // violet-400
-  sessions:  '#34d399',  // emerald-400
-  exports:   '#60a5fa',  // blue-400
-  stepLib:   '#fb923c',  // orange-400
-  scripts:   '#2dd4bf',  // teal-400
-  scriptBuilder: '#e879f9',  // fuchsia-400
-  analytics: '#38bdf8',  // sky-400
-  guides:    '#a3e635',  // lime-400
-  feedback:  '#818cf8',  // indigo-400
-} as const
+/* ── Types ──────────────────────────────────────────── */
+
+interface NavSubItem {
+  href: string
+  label: string
+  count?: number
+}
+
+interface NavEntry {
+  href: string
+  icon: LucideIcon
+  label: string
+  shortLabel: string
+  badge?: number
+  matchPaths?: string[]
+  children?: NavSubItem[]
+}
+
+interface NavSection {
+  title: string
+  items: NavEntry[]
+}
+
+/* ── Sidebar component ──────────────────────────────── */
 
 export function Sidebar() {
-  const sidebarCollapsed = useUserPreferencesStore(s => s.sidebarCollapsed)
-  const toggleSidebar = useUserPreferencesStore(s => s.toggleSidebar)
   const location = useLocation()
+  const sidebarPinned = useUserPreferencesStore(s => s.sidebarPinned)
+  const toggleSidebarPinned = useUserPreferencesStore(s => s.toggleSidebarPinned)
 
   const [stats, setStats] = useState<SidebarStatsResponse | null>(null)
+  const [flyoutIndex, setFlyoutIndex] = useState<string | null>(null)
+  const flyoutTimeout = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const sidebarRef = useRef<HTMLElement>(null)
+
+  /* ── Stats fetching ───────────────────────────────── */
 
   const refreshStats = useCallback(() => {
     sidebarApi.getStats().then(setStats).catch(() => {})
   }, [])
 
-  // Fetch sidebar stats — refreshes on navigation
-  useEffect(() => {
-    refreshStats()
-  }, [location.pathname, refreshStats])
+  useEffect(() => { refreshStats() }, [location.pathname, refreshStats])
 
-  // Refresh when sessions are created or completed
   useEffect(() => {
     window.addEventListener('session-changed', refreshStats)
     return () => window.removeEventListener('session-changed', refreshStats)
   }, [refreshStats])
 
-  const handleSidebarWheel = (e: React.WheelEvent<HTMLElement>) => {
-    const sidebar = e.currentTarget
-    const canSidebarScroll = sidebar.scrollHeight > sidebar.clientHeight
-    const atTop = sidebar.scrollTop <= 0
-    const atBottom = sidebar.scrollTop + sidebar.clientHeight >= sidebar.scrollHeight - 1
+  /* ── Navigation data ──────────────────────────────── */
 
-    // If sidebar can't consume wheel movement, forward it to main content scroller.
-    if (!canSidebarScroll || (e.deltaY < 0 && atTop) || (e.deltaY > 0 && atBottom)) {
+  const sections: NavSection[] = [
+    {
+      title: 'RESOLVE',
+      items: [
+        { href: '/', icon: LayoutGrid, label: 'Dashboard', shortLabel: 'Dash' },
+        { href: '/sessions', icon: Clock, label: 'Active Sessions', shortLabel: 'Sessions', badge: stats?.active_count || undefined, matchPaths: ['/sessions'] },
+        { href: '/escalations', icon: AlertTriangle, label: 'Escalations', shortLabel: 'Escal', badge: stats?.escalation_count || undefined },
+      ],
+    },
+    {
+      title: 'KNOWLEDGE',
+      items: [
+        {
+          href: '/trees', icon: GitBranch, label: 'Flows', shortLabel: 'Flows',
+          badge: stats?.tree_counts.total || undefined,
+          matchPaths: ['/trees', '/flows', '/my-trees'],
+          children: [
+            { href: '/trees', label: 'All Flows' },
+            { 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', icon: Layers, label: 'Step Library', shortLabel: 'Steps' },
+        { href: '/scripts', icon: Code2, label: 'Scripts', shortLabel: 'Scripts' },
+        { href: '/script-builder', icon: Wand2, label: 'Script Builder', shortLabel: 'Builder' },
+        { href: '/review-queue', icon: ListChecks, label: 'Review Queue', shortLabel: 'Review' },
+      ],
+    },
+    {
+      title: 'INSIGHTS',
+      items: [
+        { href: '/shares', icon: Download, label: 'Exports', shortLabel: 'Export' },
+        { href: '/analytics', icon: BarChart3, label: 'Analytics', shortLabel: 'Stats' },
+        { href: '/analytics/flowpilot', icon: Rocket, label: 'FlowPilot Analytics', shortLabel: 'FPilot' },
+      ],
+    },
+  ]
+
+  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' },
+  ]
+
+  /* ── Active detection ─────────────────────────────── */
+
+  const isActive = (item: NavEntry) => {
+    if (item.matchPaths) return item.matchPaths.some(p => location.pathname.startsWith(p))
+    if (item.href === '/') return location.pathname === '/'
+    return location.pathname.startsWith(item.href)
+  }
+
+  const isChildActive = (child: NavSubItem) => {
+    const fullPath = location.pathname + location.search
+    return fullPath === child.href || fullPath.startsWith(child.href + '&')
+  }
+
+  /* ── Flyout management ────────────────────────────── */
+
+  const openFlyout = (key: string) => {
+    if (flyoutTimeout.current) clearTimeout(flyoutTimeout.current)
+    setFlyoutIndex(key)
+  }
+
+  const closeFlyout = () => {
+    flyoutTimeout.current = setTimeout(() => setFlyoutIndex(null), 120)
+  }
+
+  const keepFlyout = () => {
+    if (flyoutTimeout.current) clearTimeout(flyoutTimeout.current)
+  }
+
+  /* Close flyout on Escape */
+  useEffect(() => {
+    const handleKey = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') setFlyoutIndex(null)
+    }
+    document.addEventListener('keydown', handleKey)
+    return () => document.removeEventListener('keydown', handleKey)
+  }, [])
+
+  /* ── Wheel forwarding (when sidebar can't scroll) ── */
+
+  const handleWheel = (e: React.WheelEvent<HTMLElement>) => {
+    const el = e.currentTarget
+    const canScroll = el.scrollHeight > el.clientHeight
+    const atTop = el.scrollTop <= 0
+    const atBottom = el.scrollTop + el.clientHeight >= el.scrollHeight - 1
+    if (!canScroll || (e.deltaY < 0 && atTop) || (e.deltaY > 0 && atBottom)) {
       const main = document.querySelector('.main-content') as HTMLElement | null
-      if (main) {
-        main.scrollTop += e.deltaY
-        e.preventDefault()
-      }
+      if (main) { main.scrollTop += e.deltaY; e.preventDefault() }
     }
   }
 
+  /* ── Render helpers ───────────────────────────────── */
+
+  const renderRailItem = (item: NavEntry, key: string) => {
+    const active = isActive(item)
+    const Icon = item.icon
+    const hasChildren = item.children && item.children.length > 0
+
+    return (
+      <div
+        key={key}
+        className="relative"
+        onMouseEnter={() => hasChildren && !sidebarPinned ? openFlyout(key) : undefined}
+        onMouseLeave={() => hasChildren && !sidebarPinned ? closeFlyout() : undefined}
+      >
+        <Link
+          to={item.href}
+          onMouseEnter={() => prefetchForRoute(item.href)}
+          onFocus={() => hasChildren && !sidebarPinned ? openFlyout(key) : undefined}
+          onBlur={() => hasChildren && !sidebarPinned ? closeFlyout() : undefined}
+          className={cn(
+            'group relative flex flex-col items-center justify-center rounded-lg px-1 py-2 transition-all duration-150',
+            active
+              ? 'bg-[rgba(34,211,238,0.10)] text-[#67e8f9]'
+              : 'text-[#6b7280] hover:text-[#848b9b]'
+          )}
+          title={item.label}
+        >
+          <span className="relative">
+            <Icon size={20} className={active ? 'opacity-100' : 'opacity-60 group-hover:opacity-85'} />
+            {item.badge !== undefined && item.badge > 0 && (
+              <span className="absolute -right-1.5 -top-1.5 flex h-4 min-w-[16px] items-center justify-center rounded-full bg-[#22d3ee] px-1 text-[0.5rem] font-bold text-[#0c0d10]">
+                {item.badge > 99 ? '99+' : item.badge}
+              </span>
+            )}
+          </span>
+          <span className="mt-1 text-[0.5625rem] font-mono leading-tight truncate max-w-[60px]">
+            {item.shortLabel}
+          </span>
+        </Link>
+
+        {/* Flyout panel (icon rail only) */}
+        {hasChildren && !sidebarPinned && flyoutIndex === key && (
+          <div
+            className="fixed z-50 ml-1"
+            style={{
+              left: '72px',
+              top: sidebarRef.current
+                ? (() => {
+                    const itemEl = sidebarRef.current.querySelector(`[data-flyout-key="${key}"]`)
+                    if (itemEl) {
+                      const rect = itemEl.getBoundingClientRect()
+                      return `${rect.top}px`
+                    }
+                    return '0px'
+                  })()
+                : '0px',
+              maxHeight: '70vh',
+              overflowY: 'auto',
+            }}
+            onMouseEnter={keepFlyout}
+            onMouseLeave={closeFlyout}
+          >
+            <div
+              className="w-[220px] rounded-lg p-2 animate-fade-in"
+              style={{
+                background: '#14161d',
+                border: '1px solid #1e2130',
+                boxShadow: '0 4px 12px rgba(0,0,0,0.3)',
+              }}
+            >
+              {item.children!.map(child => (
+                <Link
+                  key={child.href}
+                  to={child.href}
+                  className={cn(
+                    'flex items-center justify-between rounded-md px-3 py-2 text-[0.8125rem] transition-colors',
+                    isChildActive(child)
+                      ? 'bg-[rgba(34,211,238,0.10)] text-[#67e8f9]'
+                      : 'text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]'
+                  )}
+                >
+                  <span>{child.label}</span>
+                  {child.count !== undefined && (
+                    <span className="text-[0.6875rem] font-mono text-[#4f5666]">{child.count}</span>
+                  )}
+                </Link>
+              ))}
+            </div>
+          </div>
+        )}
+      </div>
+    )
+  }
+
+  const renderPinnedItem = (item: NavEntry, key: string) => {
+    const active = isActive(item)
+    const Icon = item.icon
+    const fullPath = location.pathname + location.search
+    const activeChild = item.children?.find(c => fullPath === c.href || fullPath.startsWith(c.href + '&'))
+    const isParentDimmed = !!activeChild && active
+
+    return (
+      <div key={key} className="group/nav">
+        <Link
+          to={item.href}
+          onMouseEnter={() => prefetchForRoute(item.href)}
+          className={cn(
+            'group relative flex items-center gap-3 rounded-lg px-3 py-2 text-[0.8125rem] font-medium transition-all duration-150',
+            active
+              ? isParentDimmed
+                ? 'bg-[rgba(34,211,238,0.05)] text-[#e2e5eb]/70'
+                : 'bg-[rgba(34,211,238,0.10)] text-[#e2e5eb]'
+              : 'text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]'
+          )}
+        >
+          {active && !isParentDimmed && (
+            <div
+              className="absolute left-0 top-1/2 h-6 w-[3px] -translate-y-1/2"
+              style={{ background: '#22d3ee', borderRadius: '0 3px 3px 0' }}
+            />
+          )}
+          <Icon size={18} className={cn('shrink-0', active ? 'opacity-100' : 'opacity-70')} />
+          <span className="truncate">{item.label}</span>
+          {item.badge !== undefined && item.badge > 0 && (
+            <span className="ml-auto shrink-0 rounded-full px-2 text-[0.6875rem] font-mono text-[#4f5666]"
+              style={{ background: '#14161d', border: '1px solid #1e2130' }}>
+              {item.badge}
+            </span>
+          )}
+        </Link>
+
+        {/* Sub-items for pinned mode */}
+        {item.children && item.children.length > 0 && (
+          <div className={cn(
+            'mt-0.5 space-y-0.5 overflow-hidden transition-all duration-200',
+            active || activeChild
+              ? 'max-h-40 opacity-100'
+              : 'max-h-0 opacity-0 group-hover/nav:max-h-40 group-hover/nav:opacity-100'
+          )}>
+            {item.children.map(child => {
+              const childActive = isChildActive(child)
+              return (
+                <Link
+                  key={child.href}
+                  to={child.href}
+                  className={cn(
+                    'flex items-center gap-2 rounded-lg pl-9 pr-3 py-1.5 text-[0.8125rem] font-medium transition-colors',
+                    childActive
+                      ? 'bg-[rgba(34,211,238,0.10)] text-[#e2e5eb]'
+                      : 'text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]'
+                  )}
+                >
+                  <span className="truncate">{child.label}</span>
+                  {child.count !== undefined && (
+                    <span className="ml-auto shrink-0 rounded-full px-2 text-[0.6875rem] font-mono text-[#4f5666]"
+                      style={{ background: '#14161d', border: '1px solid #1e2130' }}>
+                      {child.count}
+                    </span>
+                  )}
+                </Link>
+              )
+            })}
+          </div>
+        )}
+      </div>
+    )
+  }
+
+  /* ── Flyout positioning: use data attribute for lookup ── */
+
+  const renderRailItemWithRef = (item: NavEntry, key: string) => {
+    return (
+      <div key={key} data-flyout-key={key}>
+        {renderRailItem(item, key + '-inner')}
+      </div>
+    )
+  }
+
+  /* ── Main render ──────────────────────────────────── */
+
+  if (sidebarPinned) {
+    return (
+      <nav
+        ref={sidebarRef}
+        className="sidebar flex flex-col"
+        style={{ background: '#0f1118', borderRight: '1px solid #1e2130' }}
+        onWheel={handleWheel}
+      >
+        {/* Pinned sidebar content */}
+        <div className="px-3 py-2 space-y-0.5">
+          {sections.map((section, si) => (
+            <div key={section.title}>
+              {si > 0 && (
+                <div className="font-mono text-[0.5625rem] uppercase tracking-[0.12em] text-[#4f5666] px-3 pt-3 pb-1">
+                  {section.title}
+                </div>
+              )}
+              {section.items.map((item, ii) => renderPinnedItem(item, `${si}-${ii}`))}
+            </div>
+          ))}
+        </div>
+
+        <div className="flex-1" />
+
+        {/* Footer */}
+        <div className="px-3 py-2 space-y-0.5" style={{ borderTop: '1px solid #1e2130' }}>
+          {footerItems.map((item, i) => renderPinnedItem(item, `footer-${i}`))}
+          <button
+            type="button"
+            onClick={toggleSidebarPinned}
+            className="flex w-full items-center gap-3 rounded-lg px-3 py-2 text-[0.8125rem] font-medium text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb] transition-colors"
+            title="Unpin sidebar"
+          >
+            <PinOff size={18} className="shrink-0" />
+            <span>Unpin</span>
+          </button>
+        </div>
+      </nav>
+    )
+  }
+
+  /* Icon Rail (default) */
   return (
     <nav
-      className="sidebar flex flex-col border-r"
-      style={{
-        background: 'rgba(16, 17, 20, 0.5)',
-        backdropFilter: 'var(--glass-blur-light)',
-        WebkitBackdropFilter: 'var(--glass-blur-light)',
-        borderColor: 'var(--glass-border)',
-      }}
-      onWheel={handleSidebarWheel}
+      ref={sidebarRef}
+      className="sidebar flex flex-col items-center"
+      style={{ background: '#0f1118', borderRight: '1px solid #1e2130' }}
+      onWheel={handleWheel}
     >
-      {sidebarCollapsed ? (
-        <>
-          {/* Collapsed: icon-only nav */}
-          <div className="flex flex-col items-center px-1.5 py-3 space-y-1">
-            <NavItem href="/" icon={LayoutGrid} label="Dashboard" iconColor={NAV_COLORS.dashboard} collapsed />
-            <NavItem href="/sessions" icon={Clock} label="Active Sessions" badge={stats?.active_count || undefined} iconColor={NAV_COLORS.sessions} collapsed />
-            <NavItem href="/escalations" icon={AlertTriangle} label="Escalations" badge={stats?.escalation_count || undefined} iconColor="#fbbf24" collapsed />
-            <NavItem href="/trees" icon={Network} label="Flows" matchPaths={['/trees', '/flows', '/my-trees']} iconColor={NAV_COLORS.flows} collapsed />
-            <NavItem href="/step-library" icon={Library} label="Step Library" iconColor={NAV_COLORS.stepLib} collapsed />
-            <NavItem href="/scripts" icon={Code2} label="Scripts" iconColor={NAV_COLORS.scripts} collapsed />
-            <NavItem href="/script-builder" icon={Wand2} label="Script Builder" iconColor={NAV_COLORS.scriptBuilder} collapsed />
-            <NavItem href="/review-queue" icon={ListChecks} label="Review Queue" iconColor="#fbbf24" collapsed />
-            <NavItem href="/shares" icon={FileOutput} label="Exports" iconColor={NAV_COLORS.exports} collapsed />
-            <NavItem href="/analytics" icon={BarChart3} label="Analytics" iconColor={NAV_COLORS.analytics} collapsed />
-            <NavItem href="/analytics/flowpilot" icon={TrendingUp} label="FlowPilot Analytics" iconColor="#2dd4bf" collapsed />
-            <NavItem href="/guides" icon={BookOpen} label="User Guides" iconColor={NAV_COLORS.guides} collapsed />
-            <NavItem href="/feedback" icon={MessageSquareText} label="Feedback" iconColor={NAV_COLORS.feedback} collapsed />
+      {/* 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}`))}
           </div>
-        </>
-      ) : (
-        <>
-          {/* Navigation */}
-          <div className="px-3 py-2 space-y-0.5">
-            {/* Dashboard */}
-            <NavItem href="/" icon={LayoutGrid} label="Dashboard" iconColor={NAV_COLORS.dashboard} />
+        ))}
+      </div>
 
-            {/* Resolve */}
-            <div className="font-label text-[0.5625rem] uppercase tracking-[0.12em] text-[#5a6170] px-3 pt-3 pb-1">
-              Resolve
-            </div>
-            <NavItem href="/sessions" icon={Clock} label="Active Sessions" badge={stats?.active_count || undefined} iconColor={NAV_COLORS.sessions} matchPaths={['/sessions']} />
-            <NavItem href="/escalations" icon={AlertTriangle} label="Escalations" badge={stats?.escalation_count || undefined} iconColor="#fbbf24" />
-
-            {/* Knowledge */}
-            <div className="font-label text-[0.5625rem] uppercase tracking-[0.12em] text-[#5a6170] px-3 pt-3 pb-1">
-              Knowledge
-            </div>
-            <NavItem
-              href="/trees"
-              icon={Network}
-              label="Flows"
-              badge={stats?.tree_counts.total || undefined}
-              iconColor={NAV_COLORS.flows}
-              matchPaths={['/trees', '/flows', '/my-trees']}
-              children={[
-                { 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 },
-              ]}
-            />
-            <NavItem href="/step-library" icon={Library} label="Step Library" iconColor={NAV_COLORS.stepLib} />
-            <NavItem href="/scripts" icon={Code2} label="Scripts" iconColor={NAV_COLORS.scripts} />
-            <NavItem href="/script-builder" icon={Wand2} label="Script Builder" iconColor={NAV_COLORS.scriptBuilder} />
-            <NavItem href="/review-queue" icon={ListChecks} label="Review Queue" iconColor="#fbbf24" />
-
-            {/* Insights */}
-            <div className="font-label text-[0.5625rem] uppercase tracking-[0.12em] text-[#5a6170] px-3 pt-3 pb-1">
-              Insights
-            </div>
-            <NavItem href="/shares" icon={FileOutput} label="Exports" iconColor={NAV_COLORS.exports} />
-            <NavItem href="/analytics" icon={BarChart3} label="Analytics" iconColor={NAV_COLORS.analytics} />
-            <NavItem href="/analytics/flowpilot" icon={TrendingUp} label="FlowPilot Analytics" iconColor="#2dd4bf" />
-          </div>
-        </>
-      )}
-
-      {/* Spacer — pushes footer to bottom */}
       <div className="flex-1" />
 
       {/* Footer */}
-      <div
-        className={cn(
-          "border-t",
-          sidebarCollapsed ? "px-1.5 py-2 flex flex-col items-center" : "px-3 py-2 space-y-0.5"
-        )}
-        style={{ borderColor: 'var(--glass-border)' }}
-      >
-        {!sidebarCollapsed && (
-          <>
-            <NavItem href="/guides" icon={BookOpen} label="User Guides" iconColor={NAV_COLORS.guides} />
-            <NavItem href="/feedback" icon={MessageSquareText} label="Feedback" iconColor={NAV_COLORS.feedback} />
-            <NavItem href="/account" icon={Settings} label="Account" />
-          </>
-        )}
+      <div className="flex flex-col items-center w-full px-1.5 py-2 space-y-0.5" style={{ borderTop: '1px solid #1e2130' }}>
+        {footerItems.map((item, i) => (
+          <div key={`footer-${i}`} data-flyout-key={`footer-${i}`}>
+            {renderRailItem(item, `footer-${i}-inner`)}
+          </div>
+        ))}
         <button
-          onClick={toggleSidebar}
-          className={cn(
-            "flex w-full items-center rounded-lg text-[0.8125rem] font-medium text-muted-foreground hover:bg-[var(--sidebar-hover)] hover:text-foreground transition-colors",
-            sidebarCollapsed ? "justify-center p-2.5" : "gap-3 px-3 py-2"
-          )}
-          title={sidebarCollapsed ? 'Expand sidebar' : 'Collapse sidebar'}
+          type="button"
+          onClick={toggleSidebarPinned}
+          className="flex flex-col items-center justify-center rounded-lg px-1 py-2 text-[#6b7280] hover:text-[#848b9b] transition-colors"
+          title="Pin sidebar"
         >
-          {sidebarCollapsed ? <PanelLeftOpen size={20} /> : <PanelLeftClose size={18} />}
-          {!sidebarCollapsed && <span>Collapse</span>}
+          <Pin size={18} className="opacity-60 hover:opacity-85" />
+          <span className="mt-1 text-[0.5625rem] font-mono leading-tight">Pin</span>
         </button>
       </div>
     </nav>
diff --git a/frontend/src/components/layout/TopBar.tsx b/frontend/src/components/layout/TopBar.tsx
index bc31852f..c463bdb5 100644
--- a/frontend/src/components/layout/TopBar.tsx
+++ b/frontend/src/components/layout/TopBar.tsx
@@ -35,7 +35,7 @@ export function TopBar() {
     return () => document.removeEventListener('mousedown', handleClickOutside)
   }, [userMenuOpen])
 
-  // ⌘K / Ctrl+K global shortcut
+  // Cmd+K / Ctrl+K global shortcut
   const handleGlobalKeyDown = useCallback((e: KeyboardEvent) => {
     if ((e.metaKey || e.ctrlKey) && e.key === 'k') {
       e.preventDefault()
@@ -55,12 +55,10 @@ export function TopBar() {
   return (
     <>
       <header
-        className="topbar relative z-10 flex items-center gap-4 border-b px-4"
+        className="topbar relative z-10 flex items-center gap-4 px-4"
         style={{
-          background: 'rgba(16, 17, 20, 0.6)',
-          backdropFilter: 'var(--glass-blur-strong)',
-          WebkitBackdropFilter: 'var(--glass-blur-strong)',
-          borderColor: 'var(--glass-border)',
+          background: '#0f1118',
+          borderBottom: '1px solid #1e2130',
         }}
       >
         {/* Logo area */}
@@ -68,10 +66,9 @@ export function TopBar() {
           to="/"
           className="flex items-center gap-2.5 pr-4 transition-all duration-200"
         >
-          <BrandLogo size="sm" className="h-7 w-7 shrink-0" />
-          <span className="text-sm font-heading font-bold tracking-tight whitespace-nowrap">
-            <span className="text-foreground">Resolution</span>
-            <span className="text-gradient-brand">Flow</span>
+          <BrandLogo size="sm" />
+          <span className="text-sm font-heading font-bold tracking-tight whitespace-nowrap text-[#f0f2f5]">
+            ResolutionFlow
           </span>
         </Link>
 
@@ -84,17 +81,28 @@ export function TopBar() {
           className="hidden sm:relative sm:block w-full text-left"
           style={{ maxWidth: '480px' }}
         >
-          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-muted-foreground" />
-          <div className="w-full rounded-lg border border-border bg-card py-2 pl-9 pr-14 text-[0.8125rem] text-muted-foreground cursor-pointer hover:border-primary/30 transition-colors">
-            Search flows, sessions, tags…
+          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-[#848b9b]" />
+          <div
+            className="w-full rounded-md py-2 pl-9 pr-14 text-[0.8125rem] text-[#848b9b] cursor-pointer transition-colors"
+            style={{
+              background: '#14161d',
+              border: '1px solid #1e2130',
+            }}
+            onMouseEnter={(e) => { (e.currentTarget as HTMLElement).style.borderColor = '#2a2f3d' }}
+            onMouseLeave={(e) => { (e.currentTarget as HTMLElement).style.borderColor = '#1e2130' }}
+          >
+            Search flows, sessions, tags...
           </div>
-          <span className="absolute right-3 top-1/2 -translate-y-1/2 rounded border border-border bg-background px-1.5 py-0.5 font-label text-[0.625rem] text-muted-foreground">
-            {navigator.platform?.toLowerCase().includes('mac') ? '⌘K' : 'Ctrl+K'}
+          <span
+            className="absolute right-3 top-1/2 -translate-y-1/2 rounded px-1.5 py-0.5 font-mono text-[0.625rem] text-[#4f5666]"
+            style={{ background: '#0c0d10', border: '1px solid #1e2130' }}
+          >
+            {navigator.platform?.toLowerCase().includes('mac') ? '\u2318K' : 'Ctrl+K'}
           </span>
         </button>
         <button
           onClick={() => setCommandPaletteOpen(true)}
-          className="sm:hidden rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground transition-colors"
+          className="sm:hidden rounded-lg p-2 text-[#848b9b] hover:text-[#e2e5eb] transition-colors"
           title="Search"
         >
           <Search size={18} />
@@ -107,14 +115,14 @@ export function TopBar() {
         <div className="flex items-center gap-1">
           <button
             onClick={() => setQuickLaunchOpen(true)}
-            className="rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground transition-colors"
+            className="rounded-lg p-2 text-[#848b9b] hover:bg-[#14161d] hover:text-[#e2e5eb] transition-colors"
             title="Quick Launch"
           >
             <Zap size={18} />
           </button>
           <Link
             to="/guides"
-            className="rounded-lg p-2 text-muted-foreground hover:bg-card hover:text-foreground transition-colors"
+            className="rounded-lg p-2 text-[#848b9b] hover:bg-[#14161d] hover:text-[#e2e5eb] transition-colors"
             title="User Guides"
           >
             <HelpCircle size={18} />
@@ -125,18 +133,22 @@ export function TopBar() {
           <div className="relative ml-2" ref={menuRef}>
             <button
               onClick={() => setUserMenuOpen(!userMenuOpen)}
-              className="flex h-8 w-8 items-center justify-center rounded-[10px] bg-gradient-brand text-xs font-heading font-bold text-primary-foreground hover:opacity-90 transition-opacity"
+              className="flex h-8 w-8 items-center justify-center rounded-[10px] text-xs font-heading font-bold text-white hover:opacity-90 transition-opacity"
+              style={{ background: 'linear-gradient(135deg, #06b6d4, #22d3ee)' }}
               title={user?.name || user?.email || 'User'}
             >
               {initials}
             </button>
 
             {userMenuOpen && (
-              <div className="absolute right-0 z-50 mt-2 w-56 rounded-lg border border-border bg-card p-1 shadow-xl animate-scale-in">
-                <div className="border-b border-border px-3 py-2.5 mb-1">
-                  <p className="text-sm font-medium text-foreground truncate">{user?.name || user?.email}</p>
+              <div
+                className="absolute right-0 z-50 mt-2 w-56 rounded-lg p-1 shadow-xl animate-scale-in"
+                style={{ background: '#14161d', border: '1px solid #1e2130' }}
+              >
+                <div className="px-3 py-2.5 mb-1" style={{ borderBottom: '1px solid #1e2130' }}>
+                  <p className="text-sm font-medium text-[#e2e5eb] truncate">{user?.name || user?.email}</p>
                   {effectiveRole && effectiveRole !== 'engineer' && (
-                    <span className="mt-1 inline-flex items-center gap-1 text-xs text-muted-foreground">
+                    <span className="mt-1 inline-flex items-center gap-1 text-xs text-[#848b9b]">
                       <Shield size={10} />
                       {effectiveRole === 'super_admin' ? 'Super Admin' : effectiveRole === 'owner' ? 'Owner' : 'Viewer'}
                     </span>
@@ -145,7 +157,7 @@ export function TopBar() {
                 <Link
                   to="/account"
                   onClick={() => setUserMenuOpen(false)}
-                  className="flex items-center gap-2 rounded-md px-3 py-2 text-sm text-muted-foreground hover:bg-accent hover:text-foreground"
+                  className="flex items-center gap-2 rounded-md px-3 py-2 text-sm text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]"
                 >
                   <Settings size={14} />
                   Account
@@ -154,18 +166,18 @@ export function TopBar() {
                   <Link
                     to="/admin"
                     onClick={() => setUserMenuOpen(false)}
-                    className="flex items-center gap-2 rounded-md px-3 py-2 text-sm text-muted-foreground hover:bg-accent hover:text-foreground"
+                    className="flex items-center gap-2 rounded-md px-3 py-2 text-sm text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]"
                   >
                     <Shield size={14} />
                     Admin Panel
                   </Link>
                 )}
-                <div className="border-t border-border mt-1 pt-1">
+                <div className="mt-1 pt-1" style={{ borderTop: '1px solid #1e2130' }}>
                   <button
                     onClick={handleLogout}
                     className={cn(
                       'flex w-full items-center gap-2 rounded-md px-3 py-2 text-sm',
-                      'text-muted-foreground hover:bg-accent hover:text-foreground'
+                      'text-[#848b9b] hover:bg-[#191c25] hover:text-[#e2e5eb]'
                     )}
                   >
                     <LogOut size={14} />
diff --git a/frontend/src/index.css b/frontend/src/index.css
index 045ce347..34a7fbb9 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -261,6 +261,7 @@
     --sidebar-w: 260px;
   }
 
+  /* Legacy collapsed class — kept as alias for pinned inverse */
   .app-shell--collapsed {
     grid-template-columns: 56px 1fr;
   }
diff --git a/frontend/src/store/userPreferencesStore.ts b/frontend/src/store/userPreferencesStore.ts
index ad43d6e5..f02aad81 100644
--- a/frontend/src/store/userPreferencesStore.ts
+++ b/frontend/src/store/userPreferencesStore.ts
@@ -17,6 +17,8 @@ interface UserPreferencesState {
   setPreferredEditorMode: (mode: EditorMode) => void
   sidebarCollapsed: boolean
   toggleSidebar: () => void
+  sidebarPinned: boolean
+  toggleSidebarPinned: () => void
   dashboardMyFlowsView: TreeLibraryView
   setDashboardMyFlowsView: (view: TreeLibraryView) => void
 }
@@ -34,6 +36,8 @@ export const useUserPreferencesStore = create<UserPreferencesState>()(
       setPreferredEditorMode: (mode) => set({ preferredEditorMode: mode }),
       sidebarCollapsed: false,
       toggleSidebar: () => set({ sidebarCollapsed: !get().sidebarCollapsed }),
+      sidebarPinned: false,
+      toggleSidebarPinned: () => set({ sidebarPinned: !get().sidebarPinned }),
       dashboardMyFlowsView: 'grid',
       setDashboardMyFlowsView: (view) => set({ dashboardMyFlowsView: view }),
     }),