feat: add in-app notification system with real-time delivery

Introduces a full in-app notification system with three types (simple,
boolean with server-side callbacks, navigate), three scopes (user, trip,
admin), fan-out persistence per recipient, and real-time push via
WebSocket. Includes a notification bell in the navbar, dropdown, dedicated
/notifications page, and a dev-only admin tab for testing all notification
variants.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/components/Admin/DevNotificationsPanel.tsx

@@ -0,0 +1,343 @@
+import React, { useState, useEffect } from 'react'
+import { adminApi, tripsApi } from '../../api/client'
+import { useAuthStore } from '../../store/authStore'
+import { useToast } from '../shared/Toast'
+import { Bell, Send, Zap, ArrowRight, CheckCircle, XCircle, Navigation, User } from 'lucide-react'
+
+interface Trip {
+  id: number
+  title: string
+}
+
+interface AppUser {
+  id: number
+  username: string
+  email: string
+}
+
+export default function DevNotificationsPanel(): React.ReactElement {
+  const toast = useToast()
+  const user = useAuthStore(s => s.user)
+  const [sending, setSending] = useState<string | null>(null)
+  const [trips, setTrips] = useState<Trip[]>([])
+  const [selectedTripId, setSelectedTripId] = useState<number | null>(null)
+  const [users, setUsers] = useState<AppUser[]>([])
+  const [selectedUserId, setSelectedUserId] = useState<number | null>(null)
+
+  useEffect(() => {
+    tripsApi.list().then(data => {
+      const list = (data.trips || data || []) as Trip[]
+      setTrips(list)
+      if (list.length > 0) setSelectedTripId(list[0].id)
+    }).catch(() => {})
+    adminApi.users().then(data => {
+      const list = (data.users || data || []) as AppUser[]
+      setUsers(list)
+      if (list.length > 0) setSelectedUserId(list[0].id)
+    }).catch(() => {})
+  }, [])
+
+  const send = async (label: string, payload: Record<string, unknown>) => {
+    setSending(label)
+    try {
+      await adminApi.sendTestNotification(payload)
+      toast.success(`Sent: ${label}`)
+    } catch (err: any) {
+      toast.error(err.message || 'Failed')
+    } finally {
+      setSending(null)
+    }
+  }
+
+  const buttons = [
+    {
+      label: 'Simple → Me',
+      icon: Bell,
+      color: '#6366f1',
+      payload: {
+        type: 'simple',
+        scope: 'user',
+        target: user?.id,
+        title_key: 'notifications.test.title',
+        title_params: { actor: user?.username || 'Admin' },
+        text_key: 'notifications.test.text',
+        text_params: {},
+      },
+    },
+    {
+      label: 'Boolean → Me',
+      icon: CheckCircle,
+      color: '#10b981',
+      payload: {
+        type: 'boolean',
+        scope: 'user',
+        target: user?.id,
+        title_key: 'notifications.test.booleanTitle',
+        title_params: { actor: user?.username || 'Admin' },
+        text_key: 'notifications.test.booleanText',
+        text_params: {},
+        positive_text_key: 'notifications.test.accept',
+        negative_text_key: 'notifications.test.decline',
+        positive_callback: { action: 'test_approve', payload: {} },
+        negative_callback: { action: 'test_deny', payload: {} },
+      },
+    },
+    {
+      label: 'Navigate → Me',
+      icon: Navigation,
+      color: '#f59e0b',
+      payload: {
+        type: 'navigate',
+        scope: 'user',
+        target: user?.id,
+        title_key: 'notifications.test.navigateTitle',
+        title_params: {},
+        text_key: 'notifications.test.navigateText',
+        text_params: {},
+        navigate_text_key: 'notifications.test.goThere',
+        navigate_target: '/dashboard',
+      },
+    },
+    {
+      label: 'Simple → Admins',
+      icon: Zap,
+      color: '#ef4444',
+      payload: {
+        type: 'simple',
+        scope: 'admin',
+        target: 0,
+        title_key: 'notifications.test.adminTitle',
+        title_params: {},
+        text_key: 'notifications.test.adminText',
+        text_params: { actor: user?.username || 'Admin' },
+      },
+    },
+  ]
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center gap-2 mb-2">
+        <div className="px-2 py-0.5 rounded text-xs font-mono font-bold" style={{ background: '#fbbf24', color: '#000' }}>
+          DEV ONLY
+        </div>
+        <span className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>
+          Notification Testing
+        </span>
+      </div>
+
+      <p className="text-xs" style={{ color: 'var(--text-muted)' }}>
+        Send test notifications to yourself, all admins, or trip members. These use test i18n keys.
+      </p>
+
+      {/* Quick-fire buttons */}
+      <div>
+        <h3 className="text-sm font-semibold mb-3" style={{ color: 'var(--text-secondary)' }}>Quick Send</h3>
+        <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
+          {buttons.map(btn => {
+            const Icon = btn.icon
+            return (
+              <button
+                key={btn.label}
+                onClick={() => send(btn.label, btn.payload)}
+                disabled={sending !== null}
+                className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+                style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+                onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+                onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+              >
+                <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                  style={{ background: `${btn.color}20`, color: btn.color }}>
+                  <Icon className="w-4 h-4" />
+                </div>
+                <div className="min-w-0">
+                  <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>{btn.label}</p>
+                  <p className="text-xs truncate" style={{ color: 'var(--text-faint)' }}>
+                    {btn.payload.type} · {btn.payload.scope}
+                  </p>
+                </div>
+                {sending === btn.label && (
+                  <div className="ml-auto w-4 h-4 border-2 border-slate-200 border-t-indigo-500 rounded-full animate-spin" />
+                )}
+              </button>
+            )
+          })}
+        </div>
+      </div>
+
+      {/* Trip-scoped notifications */}
+      {trips.length > 0 && (
+        <div>
+          <h3 className="text-sm font-semibold mb-3" style={{ color: 'var(--text-secondary)' }}>Trip-Scoped</h3>
+          <div className="flex gap-2 mb-2">
+            <select
+              value={selectedTripId ?? ''}
+              onChange={e => setSelectedTripId(Number(e.target.value))}
+              className="flex-1 px-3 py-2 rounded-lg border text-sm"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)', color: 'var(--text-primary)' }}
+            >
+              {trips.map(trip => (
+                <option key={trip.id} value={trip.id}>{trip.title}</option>
+              ))}
+            </select>
+          </div>
+          <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
+            <button
+              onClick={() => selectedTripId && send('Simple → Trip', {
+                type: 'simple',
+                scope: 'trip',
+                target: selectedTripId,
+                title_key: 'notifications.test.tripTitle',
+                title_params: { actor: user?.username || 'Admin' },
+                text_key: 'notifications.test.tripText',
+                text_params: { trip: trips.find(t => t.id === selectedTripId)?.title || 'Trip' },
+              })}
+              disabled={sending !== null || !selectedTripId}
+              className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+            >
+              <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                style={{ background: '#8b5cf620', color: '#8b5cf6' }}>
+                <Send className="w-4 h-4" />
+              </div>
+              <div>
+                <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>Simple → Trip Members</p>
+                <p className="text-xs" style={{ color: 'var(--text-faint)' }}>simple · trip</p>
+              </div>
+            </button>
+            <button
+              onClick={() => selectedTripId && send('Navigate → Trip', {
+                type: 'navigate',
+                scope: 'trip',
+                target: selectedTripId,
+                title_key: 'notifications.test.tripTitle',
+                title_params: { actor: user?.username || 'Admin' },
+                text_key: 'notifications.test.tripText',
+                text_params: { trip: trips.find(t => t.id === selectedTripId)?.title || 'Trip' },
+                navigate_text_key: 'notifications.test.goThere',
+                navigate_target: `/trips/${selectedTripId}`,
+              })}
+              disabled={sending !== null || !selectedTripId}
+              className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+            >
+              <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                style={{ background: '#f59e0b20', color: '#f59e0b' }}>
+                <ArrowRight className="w-4 h-4" />
+              </div>
+              <div>
+                <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>Navigate → Trip Members</p>
+                <p className="text-xs" style={{ color: 'var(--text-faint)' }}>navigate · trip</p>
+              </div>
+            </button>
+          </div>
+        </div>
+      )}
+
+      {/* User-scoped notifications */}
+      {users.length > 0 && (
+        <div>
+          <h3 className="text-sm font-semibold mb-3" style={{ color: 'var(--text-secondary)' }}>User-Scoped</h3>
+          <div className="flex gap-2 mb-2">
+            <select
+              value={selectedUserId ?? ''}
+              onChange={e => setSelectedUserId(Number(e.target.value))}
+              className="flex-1 px-3 py-2 rounded-lg border text-sm"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)', color: 'var(--text-primary)' }}
+            >
+              {users.map(u => (
+                <option key={u.id} value={u.id}>{u.username} ({u.email})</option>
+              ))}
+            </select>
+          </div>
+          <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
+            <button
+              onClick={() => selectedUserId && send(`Simple → ${users.find(u => u.id === selectedUserId)?.username}`, {
+                type: 'simple',
+                scope: 'user',
+                target: selectedUserId,
+                title_key: 'notifications.test.title',
+                title_params: { actor: user?.username || 'Admin' },
+                text_key: 'notifications.test.text',
+                text_params: {},
+              })}
+              disabled={sending !== null || !selectedUserId}
+              className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+            >
+              <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                style={{ background: '#06b6d420', color: '#06b6d4' }}>
+                <User className="w-4 h-4" />
+              </div>
+              <div>
+                <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>Simple → User</p>
+                <p className="text-xs" style={{ color: 'var(--text-faint)' }}>simple · user</p>
+              </div>
+            </button>
+            <button
+              onClick={() => selectedUserId && send(`Boolean → ${users.find(u => u.id === selectedUserId)?.username}`, {
+                type: 'boolean',
+                scope: 'user',
+                target: selectedUserId,
+                title_key: 'notifications.test.booleanTitle',
+                title_params: { actor: user?.username || 'Admin' },
+                text_key: 'notifications.test.booleanText',
+                text_params: {},
+                positive_text_key: 'notifications.test.accept',
+                negative_text_key: 'notifications.test.decline',
+                positive_callback: { action: 'test_approve', payload: {} },
+                negative_callback: { action: 'test_deny', payload: {} },
+              })}
+              disabled={sending !== null || !selectedUserId}
+              className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+            >
+              <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                style={{ background: '#10b98120', color: '#10b981' }}>
+                <CheckCircle className="w-4 h-4" />
+              </div>
+              <div>
+                <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>Boolean → User</p>
+                <p className="text-xs" style={{ color: 'var(--text-faint)' }}>boolean · user</p>
+              </div>
+            </button>
+            <button
+              onClick={() => selectedUserId && send(`Navigate → ${users.find(u => u.id === selectedUserId)?.username}`, {
+                type: 'navigate',
+                scope: 'user',
+                target: selectedUserId,
+                title_key: 'notifications.test.navigateTitle',
+                title_params: {},
+                text_key: 'notifications.test.navigateText',
+                text_params: {},
+                navigate_text_key: 'notifications.test.goThere',
+                navigate_target: '/dashboard',
+              })}
+              disabled={sending !== null || !selectedUserId}
+              className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left"
+              style={{ borderColor: 'var(--border-primary)', background: 'var(--bg-card)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}
+            >
+              <div className="w-8 h-8 rounded-lg flex items-center justify-center flex-shrink-0"
+                style={{ background: '#f59e0b20', color: '#f59e0b' }}>
+                <ArrowRight className="w-4 h-4" />
+              </div>
+              <div>
+                <p className="text-sm font-medium" style={{ color: 'var(--text-primary)' }}>Navigate → User</p>
+                <p className="text-xs" style={{ color: 'var(--text-faint)' }}>navigate · user</p>
+              </div>
+            </button>
+          </div>
+        </div>
+      )}
+    </div>
+  )
+}

client/src/components/Layout/InAppNotificationBell.tsx

@@ -0,0 +1,171 @@
+import React, { useState, useEffect } from 'react'
+import ReactDOM from 'react-dom'
+import { useNavigate } from 'react-router-dom'
+import { Bell, Trash2, CheckCheck } from 'lucide-react'
+import { useTranslation } from '../../i18n'
+import { useNotificationStore } from '../../store/notificationStore'
+import { useSettingsStore } from '../../store/settingsStore'
+import { useAuthStore } from '../../store/authStore'
+import NotificationItem from '../Notifications/NotificationItem'
+
+export default function NotificationBell(): React.ReactElement {
+  const { t } = useTranslation()
+  const navigate = useNavigate()
+  const { settings } = useSettingsStore()
+  const darkMode = settings.dark_mode
+  const dark = darkMode === true || darkMode === 'dark' || (darkMode === 'auto' && window.matchMedia('(prefers-color-scheme: dark)').matches)
+
+  const isAuthenticated = useAuthStore(s => s.isAuthenticated)
+  const { notifications, unreadCount, isLoading, fetchNotifications, fetchUnreadCount, markAllRead, deleteAll } = useNotificationStore()
+
+  const [open, setOpen] = useState(false)
+
+  useEffect(() => {
+    if (isAuthenticated) {
+      fetchUnreadCount()
+    }
+  }, [isAuthenticated])
+
+  const handleOpen = () => {
+    if (!open) {
+      fetchNotifications(true)
+    }
+    setOpen(v => !v)
+  }
+
+  const handleShowAll = () => {
+    setOpen(false)
+    navigate('/notifications')
+  }
+
+  const displayCount = unreadCount > 99 ? '99+' : unreadCount
+
+  return (
+    <div className="relative flex-shrink-0">
+      <button
+        onClick={handleOpen}
+        title={t('notifications.title')}
+        className="relative p-2 rounded-lg transition-colors"
+        style={{ color: 'var(--text-muted)' }}
+        onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+        onMouseLeave={e => e.currentTarget.style.background = 'transparent'}
+      >
+        <Bell className="w-4 h-4" />
+        {unreadCount > 0 && (
+          <span
+            className="absolute -top-0.5 -right-0.5 flex items-center justify-center rounded-full text-white font-bold"
+            style={{
+              background: '#ef4444',
+              fontSize: 9,
+              minWidth: 14,
+              height: 14,
+              padding: '0 3px',
+              lineHeight: 1,
+            }}
+          >
+            {displayCount}
+          </span>
+        )}
+      </button>
+
+      {open && ReactDOM.createPortal(
+        <>
+          <div style={{ position: 'fixed', inset: 0, zIndex: 9998 }} onClick={() => setOpen(false)} />
+          <div
+            className="rounded-xl shadow-xl border overflow-hidden"
+            style={{
+              position: 'fixed',
+              top: 'var(--nav-h)',
+              right: 8,
+              width: 360,
+              maxWidth: 'calc(100vw - 16px)',
+              maxHeight: 'min(480px, calc(100vh - var(--nav-h) - 16px))',
+              zIndex: 9999,
+              background: 'var(--bg-card)',
+              borderColor: 'var(--border-primary)',
+              display: 'flex',
+              flexDirection: 'column',
+            }}
+          >
+            {/* Header */}
+            <div
+              className="flex items-center justify-between px-4 py-3 flex-shrink-0"
+              style={{ borderBottom: '1px solid var(--border-secondary)' }}
+            >
+              <span className="text-sm font-semibold" style={{ color: 'var(--text-primary)' }}>
+                {t('notifications.title')}
+                {unreadCount > 0 && (
+                  <span className="ml-2 px-1.5 py-0.5 rounded-full text-xs font-medium"
+                    style={{ background: '#6366f1', color: '#fff' }}>
+                    {unreadCount}
+                  </span>
+                )}
+              </span>
+              <div className="flex items-center gap-1">
+                {unreadCount > 0 && (
+                  <button
+                    onClick={markAllRead}
+                    title={t('notifications.markAllRead')}
+                    className="p-1.5 rounded-lg transition-colors"
+                    style={{ color: 'var(--text-muted)' }}
+                    onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+                    onMouseLeave={e => e.currentTarget.style.background = 'transparent'}
+                  >
+                    <CheckCheck className="w-3.5 h-3.5" />
+                  </button>
+                )}
+                {notifications.length > 0 && (
+                  <button
+                    onClick={deleteAll}
+                    title={t('notifications.deleteAll')}
+                    className="p-1.5 rounded-lg transition-colors"
+                    style={{ color: 'var(--text-muted)' }}
+                    onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+                    onMouseLeave={e => e.currentTarget.style.background = 'transparent'}
+                  >
+                    <Trash2 className="w-3.5 h-3.5" />
+                  </button>
+                )}
+              </div>
+            </div>
+
+            {/* Notification list */}
+            <div className="overflow-y-auto flex-1">
+              {isLoading && notifications.length === 0 ? (
+                <div className="flex items-center justify-center py-10">
+                  <div className="w-5 h-5 border-2 border-slate-200 border-t-indigo-500 rounded-full animate-spin" />
+                </div>
+              ) : notifications.length === 0 ? (
+                <div className="flex flex-col items-center justify-center py-10 px-4 text-center gap-2">
+                  <Bell className="w-8 h-8" style={{ color: 'var(--text-faint)' }} />
+                  <p className="text-sm font-medium" style={{ color: 'var(--text-muted)' }}>{t('notifications.empty')}</p>
+                  <p className="text-xs" style={{ color: 'var(--text-faint)' }}>{t('notifications.emptyDescription')}</p>
+                </div>
+              ) : (
+                notifications.slice(0, 10).map(n => (
+                  <NotificationItem key={n.id} notification={n} onClose={() => setOpen(false)} />
+                ))
+              )}
+            </div>
+
+            {/* Footer */}
+            <button
+              onClick={handleShowAll}
+              className="w-full py-2.5 text-xs font-medium transition-colors flex-shrink-0"
+              style={{
+                borderTop: '1px solid var(--border-secondary)',
+                color: '#6366f1',
+                background: 'transparent',
+              }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = 'transparent'}
+            >
+              {t('notifications.showAll')}
+            </button>
+          </div>
+        </>,
+        document.body
+      )}
+    </div>
+  )
+}

client/src/components/Layout/Navbar.tsx

@@ -7,6 +7,7 @@ import { useAddonStore } from '../../store/addonStore'
 import { useTranslation } from '../../i18n'
 import { Plane, LogOut, Settings, ChevronDown, Shield, ArrowLeft, Users, Moon, Sun, Monitor, CalendarDays, Briefcase, Globe } from 'lucide-react'
 import type { LucideIcon } from 'lucide-react'
+import NotificationBell from './NotificationBell'
 
 const ADDON_ICONS: Record<string, LucideIcon> = { CalendarDays, Briefcase, Globe }
 
@@ -163,6 +164,9 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
         {dark ? <Sun className="w-4 h-4" /> : <Moon className="w-4 h-4" />}
       </button>
 
+      {/* Notification bell */}
+      {user && <NotificationBell />}
+
       {/* User menu */}
       {user && (
         <div className="relative">

client/src/components/Notifications/InAppNotificationItem.tsx

@@ -0,0 +1,195 @@
+import React, { useState } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { User, Check, X, ArrowRight, Trash2, CheckCheck } from 'lucide-react'
+import { useTranslation } from '../../i18n'
+import { useNotificationStore, InAppNotification } from '../../store/notificationStore'
+import { useSettingsStore } from '../../store/settingsStore'
+
+function relativeTime(dateStr: string, locale: string): string {
+  const diff = Date.now() - new Date(dateStr).getTime()
+  const minutes = Math.floor(diff / 60000)
+  if (minutes < 1) return locale === 'ar' ? 'الآن' : 'just now'
+  if (minutes < 60) return `${minutes}m`
+  const hours = Math.floor(minutes / 60)
+  if (hours < 24) return `${hours}h`
+  const days = Math.floor(hours / 24)
+  return `${days}d`
+}
+
+interface NotificationItemProps {
+  notification: InAppNotification
+  onClose?: () => void
+}
+
+export default function NotificationItem({ notification, onClose }: NotificationItemProps): React.ReactElement {
+  const { t, locale } = useTranslation()
+  const navigate = useNavigate()
+  const { settings } = useSettingsStore()
+  const darkMode = settings.dark_mode
+  const dark = darkMode === true || darkMode === 'dark' || (darkMode === 'auto' && window.matchMedia('(prefers-color-scheme: dark)').matches)
+  const [responding, setResponding] = useState(false)
+
+  const { markRead, markUnread, deleteNotification, respondToBoolean } = useNotificationStore()
+
+  const handleNavigate = async () => {
+    if (!notification.is_read) await markRead(notification.id)
+    if (notification.navigate_target) {
+      navigate(notification.navigate_target)
+      onClose?.()
+    }
+  }
+
+  const handleRespond = async (response: 'positive' | 'negative') => {
+    if (responding || notification.response !== null) return
+    setResponding(true)
+    await respondToBoolean(notification.id, response)
+    setResponding(false)
+  }
+
+  const titleText = t(notification.title_key, notification.title_params)
+  const bodyText = t(notification.text_key, notification.text_params)
+  const hasUnknownTitle = titleText === notification.title_key
+  const hasUnknownBody = bodyText === notification.text_key
+
+  return (
+    <div
+      className="relative px-4 py-3 transition-colors"
+      style={{
+        background: notification.is_read ? 'transparent' : (dark ? 'rgba(99,102,241,0.07)' : 'rgba(99,102,241,0.05)'),
+        borderBottom: '1px solid var(--border-secondary)',
+      }}
+    >
+      {/* Unread dot */}
+      {!notification.is_read && (
+        <div className="absolute left-2 top-1/2 -translate-y-1/2 w-1.5 h-1.5 rounded-full" style={{ background: '#6366f1' }} />
+      )}
+
+      <div className="flex gap-3 items-start">
+        {/* Sender avatar */}
+        <div className="flex-shrink-0 mt-0.5">
+          {notification.sender_avatar ? (
+            <img
+              src={notification.sender_avatar}
+              alt=""
+              className="w-8 h-8 rounded-full object-cover"
+            />
+          ) : (
+            <div
+              className="w-8 h-8 rounded-full flex items-center justify-center text-xs font-bold"
+              style={{ background: dark ? '#27272a' : '#f1f5f9', color: 'var(--text-muted)' }}
+            >
+              {notification.sender_username
+                ? notification.sender_username.charAt(0).toUpperCase()
+                : <User className="w-4 h-4" />
+              }
+            </div>
+          )}
+        </div>
+
+        {/* Content */}
+        <div className="flex-1 min-w-0">
+          <div className="flex items-start justify-between gap-2">
+            <p className="text-sm font-medium leading-snug" style={{ color: 'var(--text-primary)' }}>
+              {hasUnknownTitle ? notification.title_key : titleText}
+            </p>
+            <div className="flex items-center gap-0.5 flex-shrink-0">
+              <span className="text-xs mr-1" style={{ color: 'var(--text-faint)' }}>
+                {relativeTime(notification.created_at, locale)}
+              </span>
+              {!notification.is_read && (
+                <button
+                  onClick={() => markRead(notification.id)}
+                  title={t('notifications.markRead')}
+                  className="p-1 rounded transition-colors"
+                  style={{ color: 'var(--text-faint)' }}
+                  onMouseEnter={e => { e.currentTarget.style.background = 'var(--bg-hover)'; e.currentTarget.style.color = '#6366f1' }}
+                  onMouseLeave={e => { e.currentTarget.style.background = 'transparent'; e.currentTarget.style.color = 'var(--text-faint)' }}
+                >
+                  <CheckCheck className="w-3.5 h-3.5" />
+                </button>
+              )}
+              <button
+                onClick={() => deleteNotification(notification.id)}
+                title={t('notifications.delete')}
+                className="p-1 rounded transition-colors"
+                style={{ color: 'var(--text-faint)' }}
+                onMouseEnter={e => { e.currentTarget.style.background = 'rgba(239,68,68,0.1)'; e.currentTarget.style.color = '#ef4444' }}
+                onMouseLeave={e => { e.currentTarget.style.background = 'transparent'; e.currentTarget.style.color = 'var(--text-faint)' }}
+              >
+                <Trash2 className="w-3.5 h-3.5" />
+              </button>
+            </div>
+          </div>
+
+          <p className="text-xs mt-0.5 leading-relaxed" style={{ color: 'var(--text-muted)' }}>
+            {hasUnknownBody ? notification.text_key : bodyText}
+          </p>
+
+          {/* Boolean actions */}
+          {notification.type === 'boolean' && notification.positive_text_key && notification.negative_text_key && (
+            <div className="flex gap-2 mt-2">
+              <button
+                onClick={() => handleRespond('positive')}
+                disabled={responding || notification.response !== null}
+                className="flex items-center gap-1 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
+                style={{
+                  background: notification.response === 'positive'
+                    ? '#6366f1'
+                    : notification.response === 'negative'
+                      ? (dark ? '#27272a' : '#f1f5f9')
+                      : (dark ? '#27272a' : '#f1f5f9'),
+                  color: notification.response === 'positive'
+                    ? '#fff'
+                    : notification.response === 'negative'
+                      ? 'var(--text-faint)'
+                      : 'var(--text-secondary)',
+                  opacity: notification.response === 'negative' ? 0.5 : 1,
+                  cursor: notification.response !== null || responding ? 'default' : 'pointer',
+                }}
+              >
+                <Check className="w-3 h-3" />
+                {t(notification.positive_text_key)}
+              </button>
+              <button
+                onClick={() => handleRespond('negative')}
+                disabled={responding || notification.response !== null}
+                className="flex items-center gap-1 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
+                style={{
+                  background: notification.response === 'negative'
+                    ? '#ef4444'
+                    : notification.response === 'positive'
+                      ? (dark ? '#27272a' : '#f1f5f9')
+                      : (dark ? '#27272a' : '#f1f5f9'),
+                  color: notification.response === 'negative'
+                    ? '#fff'
+                    : notification.response === 'positive'
+                      ? 'var(--text-faint)'
+                      : 'var(--text-secondary)',
+                  opacity: notification.response === 'positive' ? 0.5 : 1,
+                  cursor: notification.response !== null || responding ? 'default' : 'pointer',
+                }}
+              >
+                <X className="w-3 h-3" />
+                {t(notification.negative_text_key)}
+              </button>
+            </div>
+          )}
+
+          {/* Navigate action */}
+          {notification.type === 'navigate' && notification.navigate_text_key && notification.navigate_target && (
+            <button
+              onClick={handleNavigate}
+              className="flex items-center gap-1 mt-2 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
+              style={{ background: dark ? '#27272a' : '#f1f5f9', color: 'var(--text-secondary)' }}
+              onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
+              onMouseLeave={e => e.currentTarget.style.background = dark ? '#27272a' : '#f1f5f9'}
+            >
+              <ArrowRight className="w-3 h-3" />
+              {t(notification.navigate_text_key)}
+            </button>
+          )}
+        </div>
+      </div>
+    </div>
+  )
+}