diff --git a/src/app/globals.css b/src/app/globals.css
new file mode 100644
index 0000000..f161468
--- /dev/null
+++ b/src/app/globals.css
@@ -0,0 +1,249 @@
+:root {
+  --pp-shadow-soft: 0 1px 2px rgba(15, 23, 42, 0.04),
+    0 4px 12px -2px rgba(15, 23, 42, 0.06);
+  --pp-shadow-elevated: 0 12px 32px -12px rgba(15, 23, 42, 0.18),
+    0 2px 6px -2px rgba(15, 23, 42, 0.08);
+  --pp-shadow-brand: 0 8px 24px -8px rgba(255, 107, 0, 0.45);
+}
+
+* {
+  box-sizing: border-box;
+}
+
+html,
+body {
+  margin: 0;
+  padding: 0;
+  scroll-behavior: smooth;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  text-rendering: optimizeLegibility;
+}
+
+body {
+  min-height: 100vh;
+  overflow-x: hidden;
+}
+
+::selection {
+  background: rgba(255, 107, 0, 0.25);
+  color: inherit;
+}
+
+::-webkit-scrollbar {
+  width: 10px;
+  height: 10px;
+}
+::-webkit-scrollbar-track {
+  background: transparent;
+}
+::-webkit-scrollbar-thumb {
+  background: rgba(120, 120, 120, 0.35);
+  border-radius: 8px;
+  border: 2px solid transparent;
+  background-clip: padding-box;
+}
+::-webkit-scrollbar-thumb:hover {
+  background: rgba(120, 120, 120, 0.6);
+  background-clip: padding-box;
+}
+
+@keyframes pp-pulse {
+  0%, 100% {
+    opacity: 0.8;
+    transform: scale(1);
+  }
+  50% {
+    opacity: 1;
+    transform: scale(1.05);
+  }
+}
+
+@keyframes pp-dot {
+  0%, 80%, 100% {
+    transform: scale(0);
+    opacity: 0.4;
+  }
+  40% {
+    transform: scale(1);
+    opacity: 1;
+  }
+}
+
+.pp-typing span {
+  display: inline-block;
+  width: 6px;
+  height: 6px;
+  margin: 0 2px;
+  border-radius: 50%;
+  background: currentColor;
+  animation: pp-dot 1.2s infinite ease-in-out;
+}
+.pp-typing span:nth-child(2) {
+  animation-delay: 0.15s;
+}
+.pp-typing span:nth-child(3) {
+  animation-delay: 0.3s;
+}
+
+.pp-grid-bg {
+  background-image: radial-gradient(
+    circle at 1px 1px,
+    rgba(120, 120, 120, 0.12) 1px,
+    transparent 0
+  );
+  background-size: 28px 28px;
+}
+
+/* ===========================
+   FullCalendar — themed to PatchPilot
+   =========================== */
+.fc {
+  font-family: inherit;
+  --fc-border-color: rgba(120, 120, 120, 0.18);
+  --fc-page-bg-color: transparent;
+  --fc-neutral-bg-color: transparent;
+  --fc-list-event-hover-bg-color: rgba(255, 107, 0, 0.06);
+  --fc-today-bg-color: rgba(255, 107, 0, 0.08);
+  --fc-now-indicator-color: #ff6b00;
+  --fc-event-bg-color: #ff6b00;
+  --fc-event-border-color: #ff6b00;
+  --fc-event-text-color: #ffffff;
+  color: inherit;
+  font-size: 0.85rem;
+}
+
+.fc .fc-toolbar {
+  margin-bottom: 14px;
+  gap: 8px;
+}
+.fc .fc-toolbar-chunk {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+}
+.fc .fc-toolbar-title {
+  font-size: 0.95rem !important;
+  font-weight: 700 !important;
+  letter-spacing: -0.005em;
+}
+
+.fc .fc-button {
+  background: transparent !important;
+  border: 1px solid var(--fc-border-color) !important;
+  color: inherit !important;
+  text-transform: none !important;
+  font-weight: 600 !important;
+  font-size: 0.78rem !important;
+  padding: 4px 10px !important;
+  border-radius: 8px !important;
+  box-shadow: none !important;
+  transition: background-color 0.15s, border-color 0.15s, color 0.15s;
+}
+.fc .fc-button:not(:disabled):hover {
+  background: rgba(255, 107, 0, 0.08) !important;
+  border-color: rgba(255, 107, 0, 0.45) !important;
+  color: #ff6b00 !important;
+}
+.fc .fc-button-primary:not(:disabled).fc-button-active {
+  background: #ff6b00 !important;
+  border-color: #ff6b00 !important;
+  color: #fff !important;
+}
+.fc .fc-button-group > .fc-button {
+  border-radius: 0 !important;
+}
+.fc .fc-button-group > .fc-button:first-child {
+  border-top-left-radius: 8px !important;
+  border-bottom-left-radius: 8px !important;
+}
+.fc .fc-button-group > .fc-button:last-child {
+  border-top-right-radius: 8px !important;
+  border-bottom-right-radius: 8px !important;
+}
+
+.fc .fc-col-header-cell {
+  background: transparent !important;
+  font-weight: 700;
+  font-size: 0.72rem;
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  color: rgba(120, 120, 120, 1);
+  padding: 8px 0 !important;
+}
+.fc .fc-col-header-cell-cushion {
+  text-decoration: none !important;
+  color: inherit !important;
+  padding: 4px 8px !important;
+}
+
+.fc-theme-standard td,
+.fc-theme-standard th,
+.fc-theme-standard .fc-scrollgrid {
+  border-color: var(--fc-border-color) !important;
+}
+
+.fc .fc-daygrid-day-frame {
+  min-height: 56px;
+  padding: 2px;
+}
+.fc .fc-daygrid-day-number {
+  text-decoration: none !important;
+  color: inherit !important;
+  font-size: 0.78rem;
+  font-weight: 600;
+  padding: 4px 6px !important;
+  opacity: 0.8;
+}
+.fc .fc-day-today .fc-daygrid-day-number {
+  background: #ff6b00;
+  color: #fff !important;
+  border-radius: 8px;
+  width: 22px;
+  height: 22px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0 !important;
+  opacity: 1;
+}
+.fc .fc-day-other .fc-daygrid-day-number {
+  opacity: 0.35;
+}
+
+.fc-event {
+  border-radius: 6px !important;
+  border: none !important;
+  font-size: 0.72rem !important;
+  font-weight: 600 !important;
+  padding: 2px 6px !important;
+  cursor: pointer;
+  transition: transform 0.15s, box-shadow 0.15s;
+}
+.fc-event:hover {
+  transform: translateY(-1px);
+  box-shadow: 0 6px 14px -6px rgba(0, 0, 0, 0.25);
+}
+.fc-event.fc-bg-event {
+  opacity: 0.4 !important;
+}
+
+.fc-h-event,
+.fc-v-event {
+  background: var(--fc-event-bg-color) !important;
+  border: none !important;
+}
+
+.fc .fc-timegrid-slot-label-cushion {
+  font-size: 0.72rem;
+  font-weight: 500;
+  color: rgba(120, 120, 120, 1);
+}
+
+/* Compact mode for in-modal calendar */
+.pp-calendar-compact .fc-toolbar-title {
+  font-size: 0.85rem !important;
+}
+.pp-calendar-compact .fc-daygrid-day-frame {
+  min-height: 38px;
+}
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
new file mode 100644
index 0000000..d83fc05
--- /dev/null
+++ b/src/app/layout.tsx
@@ -0,0 +1,51 @@
+import type { Metadata, Viewport } from 'next';
+import { Inter } from 'next/font/google';
+import Providers from './providers';
+import './globals.css';
+
+const inter = Inter({
+  subsets: ['latin'],
+  display: 'swap',
+  variable: '--pp-font-sans',
+});
+
+export const metadata: Metadata = {
+  title: {
+    default: 'PatchPilot — KI-gestütztes Repair Café',
+    template: '%s · PatchPilot',
+  },
+  description:
+    'Buche Werkzeuge, finde Anleitungen und repariere klüger — mit KI-gestützter Hilfe in deinem Repair Café.',
+  applicationName: 'PatchPilot',
+  keywords: ['Repair Café', 'Werkzeuge', 'Reparatur', 'KI', 'Reservierung'],
+  authors: [{ name: 'PatchPilot Team' }],
+  icons: {
+    icon: [{ url: '/logo.png', type: 'image/png' }],
+    apple: [{ url: '/logo.png', type: 'image/png' }],
+  },
+  openGraph: {
+    title: 'PatchPilot — KI-gestütztes Repair Café',
+    description: 'Buche Werkzeuge, finde Anleitungen, repariere klüger.',
+    type: 'website',
+    locale: 'de_DE',
+  },
+};
+
+export const viewport: Viewport = {
+  width: 'device-width',
+  initialScale: 1,
+  themeColor: [
+    { media: '(prefers-color-scheme: light)', color: '#F9FAFB' },
+    { media: '(prefers-color-scheme: dark)', color: '#121212' },
+  ],
+};
+
+export default function RootLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <html lang="de" className={inter.variable}>
+      <body>
+        <Providers>{children}</Providers>
+      </body>
+    </html>
+  );
+}
diff --git a/src/app/providers.tsx b/src/app/providers.tsx
new file mode 100644
index 0000000..a3ccdba
--- /dev/null
+++ b/src/app/providers.tsx
@@ -0,0 +1,12 @@
+'use client';
+
+import { I18nProvider } from '../services/i18n';
+import { ColorModeProvider } from '../services/color-mode';
+
+export default function Providers({ children }: { children: React.ReactNode }) {
+  return (
+    <I18nProvider>
+      <ColorModeProvider>{children}</ColorModeProvider>
+    </I18nProvider>
+  );
+}
diff --git a/src/config/theme.ts b/src/config/theme.ts
new file mode 100644
index 0000000..6b45b2b
--- /dev/null
+++ b/src/config/theme.ts
@@ -0,0 +1,203 @@
+import type { ThemeOptions } from '@mui/material/styles';
+
+export const brandColors = {
+  orange: '#FF6B00',
+  orangeDark: '#E55F00',
+  orangeLight: '#FFB17A',
+  green: '#2D5A27',
+  greenLight: '#4A8F3F',
+  grey: {
+    50: '#F9FAFB',
+    100: '#F3F4F6',
+    200: '#E5E7EB',
+    300: '#D1D5DB',
+    400: '#9CA3AF',
+    500: '#6B7280',
+    600: '#4B5563',
+    700: '#374151',
+    800: '#1F2937',
+    900: '#111827',
+  },
+} as const;
+
+const fontStack =
+  'var(--pp-font-sans), "Inter", "system-ui", "-apple-system", "Segoe UI", Roboto, sans-serif';
+
+const getDesignTokens = (mode: 'light' | 'dark'): ThemeOptions => {
+  const isLight = mode === 'light';
+
+  return {
+    palette: {
+      mode,
+      primary: {
+        main: brandColors.orange,
+        dark: brandColors.orangeDark,
+        light: brandColors.orangeLight,
+        contrastText: '#FFFFFF',
+      },
+      secondary: {
+        main: brandColors.green,
+        light: brandColors.greenLight,
+        contrastText: '#FFFFFF',
+      },
+      background: {
+        default: isLight ? brandColors.grey[50] : '#0B0F1A',
+        paper: isLight ? '#FFFFFF' : '#141826',
+      },
+      text: {
+        primary: isLight ? brandColors.grey[900] : '#F3F4F6',
+        secondary: isLight ? brandColors.grey[600] : brandColors.grey[400],
+      },
+      divider: isLight ? brandColors.grey[200] : 'rgba(255,255,255,0.08)',
+      success: { main: '#22C55E' },
+      warning: { main: '#F59E0B' },
+      error: { main: '#EF4444' },
+      info: { main: '#3B82F6' },
+    },
+    shape: { borderRadius: 12 },
+    typography: {
+      fontFamily: fontStack,
+      h1: { fontWeight: 800, letterSpacing: '-0.03em', lineHeight: 1.05 },
+      h2: { fontWeight: 800, letterSpacing: '-0.02em', lineHeight: 1.1 },
+      h3: { fontWeight: 700, letterSpacing: '-0.015em' },
+      h4: { fontWeight: 700, letterSpacing: '-0.01em' },
+      h5: { fontWeight: 700, letterSpacing: '-0.005em' },
+      h6: { fontWeight: 600 },
+      subtitle1: { fontWeight: 600 },
+      body1: { lineHeight: 1.6 },
+      body2: { lineHeight: 1.55 },
+      button: { textTransform: 'none', fontWeight: 600, letterSpacing: '0.005em' },
+    },
+    components: {
+      MuiCssBaseline: {
+        styleOverrides: {
+          body: {
+            background: isLight
+              ? `linear-gradient(180deg, ${brandColors.grey[50]} 0%, #F1F3F7 100%)`
+              : 'linear-gradient(180deg, #0B0F1A 0%, #0E1424 100%)',
+            backgroundAttachment: 'fixed',
+          },
+        },
+      },
+      MuiButton: {
+        defaultProps: { disableElevation: true },
+        styleOverrides: {
+          root: {
+            borderRadius: 12,
+            padding: '10px 18px',
+            fontWeight: 600,
+            transition: 'transform 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease',
+          },
+          contained: {
+            boxShadow: 'var(--pp-shadow-brand)',
+            '&:hover': {
+              boxShadow: '0 12px 28px -10px rgba(255,107,0,0.55)',
+              transform: 'translateY(-1px)',
+            },
+            '&:active': { transform: 'translateY(0)' },
+          },
+          outlined: {
+            borderColor: isLight ? brandColors.grey[300] : 'rgba(255,255,255,0.12)',
+            '&:hover': {
+              borderColor: brandColors.orange,
+              background: isLight ? 'rgba(255,107,0,0.06)' : 'rgba(255,107,0,0.1)',
+            },
+          },
+          sizeSmall: { padding: '6px 12px' },
+        },
+      },
+      MuiPaper: {
+        styleOverrides: {
+          root: {
+            backgroundImage: 'none',
+            borderRadius: 16,
+          },
+          outlined: {
+            border: `1px solid ${isLight ? brandColors.grey[200] : 'rgba(255,255,255,0.08)'}`,
+          },
+        },
+      },
+      MuiCard: {
+        styleOverrides: {
+          root: {
+            borderRadius: 16,
+            backgroundImage: 'none',
+          },
+        },
+      },
+      MuiAppBar: {
+        styleOverrides: {
+          root: {
+            backgroundImage: 'none',
+            backdropFilter: 'saturate(180%) blur(12px)',
+            WebkitBackdropFilter: 'saturate(180%) blur(12px)',
+            background: isLight ? 'rgba(255,255,255,0.78)' : 'rgba(20,24,38,0.78)',
+            borderBottom: `1px solid ${
+              isLight ? brandColors.grey[200] : 'rgba(255,255,255,0.06)'
+            }`,
+          },
+        },
+      },
+      MuiDialog: {
+        styleOverrides: {
+          paper: { borderRadius: 20 },
+        },
+      },
+      MuiTextField: {
+        defaultProps: { variant: 'outlined' },
+      },
+      MuiOutlinedInput: {
+        styleOverrides: {
+          root: {
+            borderRadius: 12,
+            transition: 'box-shadow 0.18s ease',
+            '&.Mui-focused': {
+              boxShadow: `0 0 0 3px ${isLight ? 'rgba(255,107,0,0.18)' : 'rgba(255,107,0,0.25)'}`,
+            },
+          },
+        },
+      },
+      MuiChip: {
+        styleOverrides: {
+          root: { fontWeight: 600 },
+        },
+      },
+      MuiTooltip: {
+        styleOverrides: {
+          tooltip: {
+            fontSize: '0.75rem',
+            borderRadius: 8,
+            padding: '6px 10px',
+            background: isLight ? brandColors.grey[900] : brandColors.grey[700],
+          },
+        },
+      },
+      MuiTab: {
+        styleOverrides: {
+          root: {
+            textTransform: 'none',
+            fontWeight: 600,
+            minHeight: 48,
+          },
+        },
+      },
+      MuiTableCell: {
+        styleOverrides: {
+          head: {
+            fontWeight: 700,
+            fontSize: '0.78rem',
+            letterSpacing: '0.04em',
+            textTransform: 'uppercase',
+            color: isLight ? brandColors.grey[500] : brandColors.grey[400],
+            borderBottom: `1px solid ${isLight ? brandColors.grey[200] : 'rgba(255,255,255,0.08)'}`,
+          },
+          root: {
+            borderBottom: `1px solid ${isLight ? brandColors.grey[100] : 'rgba(255,255,255,0.04)'}`,
+          },
+        },
+      },
+    },
+  };
+};
+
+export default getDesignTokens;
diff --git a/src/services/color-mode.tsx b/src/services/color-mode.tsx
new file mode 100644
index 0000000..85d8f6a
--- /dev/null
+++ b/src/services/color-mode.tsx
@@ -0,0 +1,71 @@
+'use client';
+
+import React, {
+  createContext,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+} from 'react';
+import { ThemeProvider, createTheme, CssBaseline } from '@mui/material';
+import getDesignTokens from '../config/theme';
+
+type Mode = 'light' | 'dark';
+
+interface ColorModeContextValue {
+  mode: Mode;
+  toggleColorMode: () => void;
+  setColorMode: (mode: Mode) => void;
+}
+
+const STORAGE_KEY = 'patchpilot:color-mode';
+
+const ColorModeContext = createContext<ColorModeContextValue>({
+  mode: 'light',
+  toggleColorMode: () => {},
+  setColorMode: () => {},
+});
+
+export const useColorMode = () => useContext(ColorModeContext);
+
+function detectInitialMode(): Mode {
+  if (typeof window === 'undefined') return 'light';
+  const stored = window.localStorage.getItem(STORAGE_KEY);
+  if (stored === 'light' || stored === 'dark') return stored;
+  return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+}
+
+export const ColorModeProvider = ({ children }: { children: React.ReactNode }) => {
+  const [mode, setMode] = useState<Mode>('light');
+  const [hydrated, setHydrated] = useState(false);
+
+  useEffect(() => {
+    setMode(detectInitialMode());
+    setHydrated(true);
+  }, []);
+
+  useEffect(() => {
+    if (!hydrated) return;
+    window.localStorage.setItem(STORAGE_KEY, mode);
+  }, [mode, hydrated]);
+
+  const value = useMemo<ColorModeContextValue>(
+    () => ({
+      mode,
+      toggleColorMode: () => setMode((p) => (p === 'light' ? 'dark' : 'light')),
+      setColorMode: (next) => setMode(next),
+    }),
+    [mode]
+  );
+
+  const theme = useMemo(() => createTheme(getDesignTokens(mode)), [mode]);
+
+  return (
+    <ColorModeContext.Provider value={value}>
+      <ThemeProvider theme={theme}>
+        <CssBaseline />
+        {children}
+      </ThemeProvider>
+    </ColorModeContext.Provider>
+  );
+};
diff --git a/src/services/i18n.tsx b/src/services/i18n.tsx
new file mode 100644
index 0000000..e332035
--- /dev/null
+++ b/src/services/i18n.tsx
@@ -0,0 +1,385 @@
+'use client';
+
+import {
+  createContext,
+  useContext,
+  useEffect,
+  useState,
+  ReactNode,
+  useMemo,
+} from 'react';
+
+type Language = 'de' | 'en';
+
+const translations = {
+  de: {
+    // App + Navigation
+    appName: 'PATCHPILOT',
+    tools: 'Werkzeuge',
+    chat: 'KI-Assistent',
+    admin: 'Admin',
+    logout: 'Abmelden',
+    administrator: 'Administrator',
+    guestRole: 'Gast',
+    staffRole: 'Mitarbeiter',
+    user: 'Nutzer',
+    role: 'Rolle',
+
+    // Hero
+    heroBadge: 'KI-gestützte Reparaturlösungen',
+    heroTitlePart1: 'Repariere klüger,',
+    heroTitlePart2: 'nicht härter.',
+    heroSubtitle:
+      'Dein intelligenter Begleiter für jede Reparatur. Erhalte Schritt-für-Schritt Anleitungen, Werkzeug-Empfehlungen und sofortige Hilfe.',
+    heroCTA: 'Jetzt Hilfe anfordern',
+    aiPlaceholder: 'Frage RepairBuddy nach Hilfe…',
+    miniStatInventory: 'Inventar',
+    miniStatAssistant: 'KI-Assistent',
+    miniStatResponse: 'Antwort',
+
+    // Login
+    loginWelcomeBack: 'Willkommen zurück',
+    loginSubtitle:
+      'Melde dich an, um Werkzeuge zu reservieren und mit dem KI-Assistenten zu chatten.',
+    loginDemoTitle: 'Demo-Zugänge',
+    loginDemoBody:
+      'admin / admin · vollständiger Zugriff\nguest / guest · Gast-Modus\nstaff / staff · Mitarbeiter',
+    loginError: 'Falscher Benutzername oder Passwort. (Tipp: admin/admin oder guest/guest)',
+    loginSubmit: 'Einloggen',
+    loginSubmitting: 'Einloggen…',
+
+    // Tools page
+    inventory: 'Werkzeug-Inventar',
+    inventoryHint: 'Werkzeuge verfügbar',
+    search: 'Werkzeuge durchsuchen…',
+    filter: 'Filter',
+    all: 'Alle',
+    reserve: 'Jetzt reservieren',
+    certified: 'Zertifiziert',
+    trainingMissing: 'Schulung fehlt',
+    trainingRequired: 'Einweisung benötigt',
+    homeUse: 'Heimnutzung',
+    freeAccess: 'Frei zugänglich',
+    days: 'Tage',
+    noToolsFound: 'Keine Werkzeuge gefunden. Passe Suche oder Filter an.',
+
+    // Chat
+    newChat: 'Neuer Chat',
+    chatHistory: 'Verlauf',
+    chatEmptyTitle: 'Womit darf ich helfen?',
+    chatEmptyHint:
+      'Frag mich nach Werkzeugen, Reparatur-Tipps oder beschreibe dein Problem.',
+    chatNoSessionTitle: 'Worüber sollen wir reden?',
+    chatNoSessionHint: 'Wähle einen Vorschlag unten oder schreibe deine Frage.',
+    chatRename: 'Umbenennen',
+    chatDelete: 'Löschen',
+    chatRetry: 'Letzte Anfrage erneut senden',
+    chatCopy: 'Kopieren',
+    chatCopied: 'Kopiert!',
+    chatTypingPlaceholder: 'Tippe deine Frage…',
+    modeLive: 'Live',
+    modeFallback: 'Fallback',
+    modeDemo: 'Demo',
+
+    // Reservation
+    reservation: 'Reservierung',
+    availability: 'Verfügbarkeit',
+    booked: 'Reserviert',
+    free: 'Frei',
+    from: 'Von',
+    to: 'Bis',
+    maxRental: 'Maximale Leihdauer',
+    cancel: 'Abbrechen',
+    request: 'Anfragen',
+    confirmReservation: 'Reservieren',
+    reservedSuccess: 'Reserviert!',
+    durationTotal: 'gesamt',
+    notice:
+      'Bitte bringe das Werkzeug rechtzeitig und unbeschädigt zurück.',
+
+    // Login form fields
+    username: 'Benutzername',
+    password: 'Passwort',
+    login: 'Einloggen',
+
+    // Onboarding
+    welcome: 'Willkommen bei PatchPilot!',
+    onboarding1Desc:
+      'Hier kannst du professionelle Werkzeuge für deine Reparaturen ausleihen. Achte auf die Einweisungspflicht!',
+    onboarding2Title: 'Dein Reparatur-Assistent',
+    onboarding2Desc:
+      'Nutze unseren Chatbot, um Tipps für deine Reparatur zu bekommen oder das passende Werkzeug zu finden.',
+    onboarding3Title: 'Verfügbarkeit prüfen',
+    onboarding3Desc:
+      'In unserem interaktiven Kalender siehst du sofort, wann Werkzeuge verfügbar sind.',
+    onboarding4Title: 'Admin-Funktionen',
+    onboarding4Desc:
+      'Als Administrator kannst du das gesamte System verwalten — von Werkzeugen bis hin zu KI-Wissensquellen.',
+    getStarted: 'Loslegen',
+    next: 'Weiter',
+    back: 'Zurück',
+    skip: 'Überspringen',
+    onboardingStep: 'Schritt',
+    of: 'von',
+
+    // Admin
+    adminDashboard: 'Admin Dashboard',
+    adminSubtitle: 'Verwalte Werkzeuge, Reservierungen und Wissen',
+    manageTools: 'Werkzeuge',
+    manageRAG: 'KI-Wissen',
+    manageUsers: 'Nutzer',
+    calendar: 'Kalender',
+    addTool: 'Werkzeug hinzufügen',
+    editTool: 'Werkzeug bearbeiten',
+    deleteTool: 'Werkzeug löschen',
+    confirmDelete: 'Wirklich löschen?',
+    delete: 'Löschen',
+    edit: 'Bearbeiten',
+    save: 'Speichern',
+    name: 'Name',
+    description: 'Beschreibung',
+    location: 'Standort',
+    category: 'Kategorie',
+    emoji: 'Symbol',
+    status: 'Status',
+    actions: 'Aktionen',
+    available: 'Verfügbar',
+    statsTools: 'Werkzeuge',
+    statsUsers: 'Nutzer',
+    statsActive: 'Aktive Reservierungen',
+    statsPending: 'Offen',
+    addManual: 'Dokument hochladen',
+    manualPreview: 'Vorschau',
+    forTool: 'Werkzeug',
+    title: 'Titel',
+    content: 'Inhalt',
+    certifications: 'Zertifizierungen',
+    none: 'keine',
+    pendingReservations: 'Offene Reservierungs-Anfragen',
+    approve: 'Genehmigen',
+    reject: 'Ablehnen',
+    requestedBy: 'Angefragt von',
+    period: 'Zeitraum',
+    statusRequested: 'Angefragt',
+    statusApproved: 'Genehmigt',
+    statusActive: 'Aktiv',
+    statusCompleted: 'Erledigt',
+    statusOverdue: 'Überfällig',
+    reservationCalendar: 'Reservierungskalender',
+  },
+  en: {
+    // App + Navigation
+    appName: 'PATCHPILOT',
+    tools: 'Tools',
+    chat: 'AI Assistant',
+    admin: 'Admin',
+    logout: 'Sign out',
+    administrator: 'Administrator',
+    guestRole: 'Guest',
+    staffRole: 'Staff',
+    user: 'User',
+    role: 'Role',
+
+    // Hero
+    heroBadge: 'AI-powered repair solutions',
+    heroTitlePart1: 'Repair smarter,',
+    heroTitlePart2: 'not harder.',
+    heroSubtitle:
+      'Your intelligent companion for every repair. Get step-by-step instructions, tool recommendations, and instant help.',
+    heroCTA: 'Get help now',
+    aiPlaceholder: 'Ask RepairBuddy for help…',
+    miniStatInventory: 'Inventory',
+    miniStatAssistant: 'AI assistant',
+    miniStatResponse: 'Response',
+
+    // Login
+    loginWelcomeBack: 'Welcome back',
+    loginSubtitle:
+      'Sign in to reserve tools and chat with the AI assistant.',
+    loginDemoTitle: 'Demo accounts',
+    loginDemoBody:
+      'admin / admin · full access\nguest / guest · guest mode\nstaff / staff · staff member',
+    loginError: 'Wrong username or password. (Hint: admin/admin or guest/guest)',
+    loginSubmit: 'Sign in',
+    loginSubmitting: 'Signing in…',
+
+    // Tools page
+    inventory: 'Tool Inventory',
+    inventoryHint: 'tools available',
+    search: 'Search tools…',
+    filter: 'Filter',
+    all: 'All',
+    reserve: 'Reserve now',
+    certified: 'Certified',
+    trainingMissing: 'Training missing',
+    trainingRequired: 'Training required',
+    homeUse: 'Home use',
+    freeAccess: 'Free access',
+    days: 'days',
+    noToolsFound: 'No tools found. Adjust your search or filter.',
+
+    // Chat
+    newChat: 'New chat',
+    chatHistory: 'History',
+    chatEmptyTitle: 'How can I help?',
+    chatEmptyHint:
+      'Ask me about tools, repair tips, or describe your problem.',
+    chatNoSessionTitle: 'What shall we talk about?',
+    chatNoSessionHint: 'Pick a suggestion below or type your question.',
+    chatRename: 'Rename',
+    chatDelete: 'Delete',
+    chatRetry: 'Retry last request',
+    chatCopy: 'Copy',
+    chatCopied: 'Copied!',
+    chatTypingPlaceholder: 'Type your question…',
+    modeLive: 'Live',
+    modeFallback: 'Fallback',
+    modeDemo: 'Demo',
+
+    // Reservation
+    reservation: 'Reservation',
+    availability: 'Availability',
+    booked: 'Booked',
+    free: 'Free',
+    from: 'From',
+    to: 'To',
+    maxRental: 'Max rental period',
+    cancel: 'Cancel',
+    request: 'Request',
+    confirmReservation: 'Reserve',
+    reservedSuccess: 'Reserved!',
+    durationTotal: 'total',
+    notice: 'Please return the tool on time and undamaged.',
+
+    // Login form fields
+    username: 'Username',
+    password: 'Password',
+    login: 'Sign in',
+
+    // Onboarding
+    welcome: 'Welcome to PatchPilot!',
+    onboarding1Desc:
+      'Here you can rent professional tools for your repairs. Mind the training requirements!',
+    onboarding2Title: 'Your repair assistant',
+    onboarding2Desc:
+      'Use our chatbot to get tips for your repair or find the right tool.',
+    onboarding3Title: 'Check availability',
+    onboarding3Desc:
+      'See exactly when tools are available in our interactive calendar.',
+    onboarding4Title: 'Admin features',
+    onboarding4Desc:
+      'As an administrator, you can manage the entire system — from tools to AI knowledge sources.',
+    getStarted: 'Get started',
+    next: 'Next',
+    back: 'Back',
+    skip: 'Skip',
+    onboardingStep: 'Step',
+    of: 'of',
+
+    // Admin
+    adminDashboard: 'Admin Dashboard',
+    adminSubtitle: 'Manage tools, reservations, and knowledge',
+    manageTools: 'Tools',
+    manageRAG: 'AI Knowledge',
+    manageUsers: 'Users',
+    calendar: 'Calendar',
+    addTool: 'Add tool',
+    editTool: 'Edit tool',
+    deleteTool: 'Delete tool',
+    confirmDelete: 'Really delete?',
+    delete: 'Delete',
+    edit: 'Edit',
+    save: 'Save',
+    name: 'Name',
+    description: 'Description',
+    location: 'Location',
+    category: 'Category',
+    emoji: 'Symbol',
+    status: 'Status',
+    actions: 'Actions',
+    available: 'Available',
+    statsTools: 'Tools',
+    statsUsers: 'Users',
+    statsActive: 'Active reservations',
+    statsPending: 'Pending',
+    addManual: 'Upload manual',
+    manualPreview: 'Preview',
+    forTool: 'Tool',
+    title: 'Title',
+    content: 'Content',
+    certifications: 'Certifications',
+    none: 'none',
+    pendingReservations: 'Pending reservation requests',
+    approve: 'Approve',
+    reject: 'Reject',
+    requestedBy: 'Requested by',
+    period: 'Period',
+    statusRequested: 'Requested',
+    statusApproved: 'Approved',
+    statusActive: 'Active',
+    statusCompleted: 'Completed',
+    statusOverdue: 'Overdue',
+    reservationCalendar: 'Reservation calendar',
+  },
+} as const;
+
+type TranslationKey = keyof (typeof translations)['de'];
+
+interface I18nContextType {
+  t: (key: TranslationKey) => string;
+  lang: Language;
+  setLang: (lang: Language) => void;
+}
+
+const I18nContext = createContext<I18nContextType | undefined>(undefined);
+
+const STORAGE_KEY = 'patchpilot:lang';
+
+function detectInitialLang(): Language {
+  if (typeof window === 'undefined') return 'de';
+  const stored = window.localStorage.getItem(STORAGE_KEY);
+  if (stored === 'de' || stored === 'en') return stored;
+  const browser = window.navigator.language.toLowerCase();
+  return browser.startsWith('en') ? 'en' : 'de';
+}
+
+export function I18nProvider({ children }: { children: ReactNode }) {
+  const [lang, setLangState] = useState<Language>('de');
+  const [hydrated, setHydrated] = useState(false);
+
+  useEffect(() => {
+    setLangState(detectInitialLang());
+    setHydrated(true);
+  }, []);
+
+  useEffect(() => {
+    if (!hydrated) return;
+    window.localStorage.setItem(STORAGE_KEY, lang);
+    document.documentElement.lang = lang;
+  }, [lang, hydrated]);
+
+  const value = useMemo<I18nContextType>(
+    () => ({
+      lang,
+      setLang: (next: Language) => setLangState(next),
+      t: (key: TranslationKey) => {
+        const dict = translations[lang];
+        const value = dict[key];
+        if (typeof value === 'string') return value;
+        const fallback = translations.de[key];
+        return typeof fallback === 'string' ? fallback : String(key);
+      },
+    }),
+    [lang]
+  );
+
+  return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>;
+}
+
+export function useI18n() {
+  const context = useContext(I18nContext);
+  if (!context) throw new Error('useI18n must be used within I18nProvider');
+  return context;
+}
+
+export type { TranslationKey };
diff --git a/src/types/index.ts b/src/types/index.ts
new file mode 100644
index 0000000..0a032c6
--- /dev/null
+++ b/src/types/index.ts
@@ -0,0 +1,59 @@
+export type Role = 'admin' | 'staff' | 'user' | 'guest';
+
+export type ToolCategory =
+  | 'power'
+  | 'measurement'
+  | 'hand'
+  | 'electronics'
+  | 'workshop'
+  | 'garden'
+  | 'sewing'
+  | 'bike';
+
+export interface User {
+  id: string;
+  username: string;
+  role: Role;
+  trainings: string[];
+  email?: string;
+}
+
+export interface Tool {
+  id: string;
+  name: string;
+  description: string;
+  location: string;
+  category: ToolCategory;
+  trainingRequired: boolean;
+  requiredTrainingId?: string;
+  homeAllowed: boolean;
+  maxRentalDays: number;
+  emoji: string;
+}
+
+export interface Reservation {
+  id: string;
+  userId: string;
+  toolId: string;
+  startDate: string;
+  endDate: string;
+  status: 'requested' | 'approved' | 'active' | 'completed' | 'overdue';
+  note?: string;
+}
+
+export interface Manual {
+  toolId: string;
+  title?: string;
+  content: string;
+}
+
+export const CATEGORY_LABEL: Record<ToolCategory, string> = {
+  power: 'Elektrowerkzeuge',
+  measurement: 'Messen',
+  hand: 'Handwerkzeug',
+  electronics: 'Elektronik',
+  workshop: 'Werkstatt',
+  garden: 'Garten',
+  sewing: 'Nähen',
+  bike: 'Fahrrad',
+};