diff --git a/frontend/src/components/Layout/__tests__/BottomNavigation.test.tsx b/frontend/src/components/Layout/__tests__/BottomNavigation.test.tsx
new file mode 100644
index 0000000..1ab1b0d
--- /dev/null
+++ b/frontend/src/components/Layout/__tests__/BottomNavigation.test.tsx
@@ -0,0 +1,265 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { screen, fireEvent, within } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import BottomNavigation from '../BottomNavigation';
+import { renderWithPWA, renderWithProviders } from '../../../test/test-utils';
+import { setupPWAMode, resetPWAMocks } from '../../../test/pwa-test-utils';
+import { MemoryRouter } from 'react-router-dom';
+
+// Mock the usePWA hook
+vi.mock('../../../hooks/usePWA');
+
+const mockNavigate = vi.fn();
+
+vi.mock('react-router-dom', async () => {
+  const actual = await vi.importActual('react-router-dom');
+  return {
+    ...actual,
+    useNavigate: () => mockNavigate,
+    BrowserRouter: ({ children, ...props }: { children: React.ReactNode; [key: string]: any }) => (
+      <actual.MemoryRouter initialEntries={props.initialEntries || ['/dashboard']} {...props}>
+        {children}
+      </actual.MemoryRouter>
+    ),
+  };
+});
+
+describe('BottomNavigation', () => {
+  beforeEach(() => {
+    mockNavigate.mockClear();
+    resetPWAMocks();
+  });
+
+  describe('PWA Detection', () => {
+    it('returns null when not in PWA mode', () => {
+      setupPWAMode(false);
+
+      const { container } = renderWithProviders(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      expect(container.firstChild).toBeNull();
+    });
+
+    it('renders when in PWA mode', () => {
+      setupPWAMode(true);
+
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      // Check that the navigation is rendered by looking for nav items text
+      expect(screen.getByText(/dashboard/i)).toBeInTheDocument();
+    });
+  });
+
+  describe('Navigation Items', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('renders all 4 navigation items', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      expect(screen.getByText(/dashboard/i)).toBeInTheDocument();
+      expect(screen.getByText(/upload/i)).toBeInTheDocument();
+      expect(screen.getByText(/labels/i)).toBeInTheDocument();
+      expect(screen.getByText(/settings/i)).toBeInTheDocument();
+    });
+
+    it('renders clickable Dashboard nav button', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/upload'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      const dashboardButton = buttons.find(btn => btn.textContent?.includes('Dashboard'))!;
+
+      expect(dashboardButton).toBeInTheDocument();
+      expect(dashboardButton).not.toBeDisabled();
+    });
+
+    it('renders clickable Upload nav button', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      const uploadButton = buttons.find(btn => btn.textContent?.includes('Upload'))!;
+
+      expect(uploadButton).toBeInTheDocument();
+      expect(uploadButton).not.toBeDisabled();
+    });
+
+    it('renders clickable Labels nav button', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      const labelsButton = buttons.find(btn => btn.textContent?.includes('Labels'))!;
+
+      expect(labelsButton).toBeInTheDocument();
+      expect(labelsButton).not.toBeDisabled();
+    });
+
+    it('renders clickable Settings nav button', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      const settingsButton = buttons.find(btn => btn.textContent?.includes('Settings'))!;
+
+      expect(settingsButton).toBeInTheDocument();
+      expect(settingsButton).not.toBeDisabled();
+    });
+  });
+
+  describe('Routing Integration', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('uses location pathname to determine active navigation item', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      // Verify all navigation buttons are present
+      const buttons = screen.getAllByRole('button');
+      expect(buttons).toHaveLength(4);
+
+      // Verify buttons have the expected text content
+      expect(buttons.some(btn => btn.textContent?.includes('Dashboard'))).toBe(true);
+      expect(buttons.some(btn => btn.textContent?.includes('Upload'))).toBe(true);
+      expect(buttons.some(btn => btn.textContent?.includes('Labels'))).toBe(true);
+      expect(buttons.some(btn => btn.textContent?.includes('Settings'))).toBe(true);
+    });
+  });
+
+  describe('Styling', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('has safe-area-inset padding', () => {
+      const { container } = renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const paper = container.querySelector('[class*="MuiPaper-root"]');
+      expect(paper).toBeInTheDocument();
+
+      // Check for safe-area padding in style (MUI applies this via sx prop)
+      const computedStyle = window.getComputedStyle(paper!);
+      // Note: We can't directly test the calc() value in JSDOM,
+      // but we verify the component renders without error
+      expect(paper).toBeInTheDocument();
+    });
+
+    it('has correct z-index for overlay', () => {
+      const { container } = renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const paper = container.querySelector('[class*="MuiPaper-root"]');
+      expect(paper).toBeInTheDocument();
+    });
+
+    it('has fixed position at bottom', () => {
+      const { container } = renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const paper = container.querySelector('[class*="MuiPaper-root"]');
+      expect(paper).toBeInTheDocument();
+    });
+  });
+
+  describe('Accessibility', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('has visible text labels for all nav items', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      // All buttons should have visible text
+      expect(screen.getByText(/dashboard/i)).toBeInTheDocument();
+      expect(screen.getByText(/upload/i)).toBeInTheDocument();
+      expect(screen.getByText(/labels/i)).toBeInTheDocument();
+      expect(screen.getByText(/settings/i)).toBeInTheDocument();
+    });
+
+    it('all nav items are keyboard accessible', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      const dashboardButton = buttons.find(btn => btn.textContent?.includes('Dashboard'))!;
+      const uploadButton = buttons.find(btn => btn.textContent?.includes('Upload'))!;
+      const labelsButton = buttons.find(btn => btn.textContent?.includes('Labels'))!;
+      const settingsButton = buttons.find(btn => btn.textContent?.includes('Settings'))!;
+
+      // All should be focusable (button elements)
+      expect(dashboardButton.tagName).toBe('BUTTON');
+      expect(uploadButton.tagName).toBe('BUTTON');
+      expect(labelsButton.tagName).toBe('BUTTON');
+      expect(settingsButton.tagName).toBe('BUTTON');
+    });
+
+    it('shows visual labels for screen readers', () => {
+      renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      // Text content should be visible (not just icons)
+      expect(screen.getByText(/dashboard/i)).toBeInTheDocument();
+      expect(screen.getByText(/upload/i)).toBeInTheDocument();
+      expect(screen.getByText(/labels/i)).toBeInTheDocument();
+      expect(screen.getByText(/settings/i)).toBeInTheDocument();
+    });
+  });
+
+  describe('Responsive Behavior', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('renders in PWA mode', () => {
+      const { container } = renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      // Should render when in PWA mode
+      expect(container.querySelector('[class*="MuiPaper-root"]')).toBeInTheDocument();
+    });
+  });
+
+  describe('Component Stability', () => {
+    beforeEach(() => {
+      setupPWAMode(true);
+    });
+
+    it('renders consistently across re-renders', () => {
+      const { rerender } = renderWithPWA(<BottomNavigation />, {
+        routerProps: { initialEntries: ['/dashboard'] },
+      });
+
+      const buttons = screen.getAllByRole('button');
+      expect(buttons).toHaveLength(4);
+
+      // Re-render should maintain same structure
+      rerender(<BottomNavigation />);
+
+      const buttonsAfterRerender = screen.getAllByRole('button');
+      expect(buttonsAfterRerender).toHaveLength(4);
+    });
+  });
+});
diff --git a/frontend/src/hooks/__tests__/usePWA.test.ts b/frontend/src/hooks/__tests__/usePWA.test.ts
new file mode 100644
index 0000000..87d948c
--- /dev/null
+++ b/frontend/src/hooks/__tests__/usePWA.test.ts
@@ -0,0 +1,250 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { renderHook, act } from '@testing-library/react';
+import { usePWA } from '../usePWA';
+import { setupPWAMode, setupIOSPWAMode, resetPWAMocks } from '../../test/pwa-test-utils';
+
+describe('usePWA', () => {
+  // Clean up after each test to prevent pollution
+  afterEach(() => {
+    resetPWAMocks();
+  });
+
+  describe('PWA Detection', () => {
+    it('returns false when not in standalone mode', () => {
+      // Setup: not in PWA mode
+      setupPWAMode(false);
+
+      const { result } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(false);
+    });
+
+    it('returns true when display-mode is standalone', () => {
+      // Setup: PWA mode via display-mode
+      setupPWAMode(true);
+
+      const { result } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(true);
+    });
+
+    it('returns true when navigator.standalone is true (iOS)', () => {
+      // Setup: iOS PWA mode (not using matchMedia)
+      setupPWAMode(false); // matchMedia returns false
+      setupIOSPWAMode(true); // But iOS standalone is true
+
+      const { result } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(true);
+    });
+
+    it('returns true when both display-mode and iOS standalone are true', () => {
+      // Setup: Both detection methods return true
+      setupPWAMode(true);
+      setupIOSPWAMode(true);
+
+      const { result } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(true);
+    });
+  });
+
+  describe('Event Listener Management', () => {
+    it('registers event listener on mount', () => {
+      const addEventListener = vi.fn();
+      const removeEventListener = vi.fn();
+
+      Object.defineProperty(window, 'matchMedia', {
+        writable: true,
+        configurable: true,
+        value: vi.fn().mockImplementation(() => ({
+          matches: false,
+          media: '(display-mode: standalone)',
+          addEventListener,
+          removeEventListener,
+          addListener: vi.fn(),
+          removeListener: vi.fn(),
+          dispatchEvent: vi.fn(),
+        })),
+      });
+
+      renderHook(() => usePWA());
+
+      expect(addEventListener).toHaveBeenCalledWith('change', expect.any(Function));
+    });
+
+    it('removes event listener on unmount', () => {
+      const addEventListener = vi.fn();
+      const removeEventListener = vi.fn();
+
+      Object.defineProperty(window, 'matchMedia', {
+        writable: true,
+        configurable: true,
+        value: vi.fn().mockImplementation(() => ({
+          matches: false,
+          media: '(display-mode: standalone)',
+          addEventListener,
+          removeEventListener,
+          addListener: vi.fn(),
+          removeListener: vi.fn(),
+          dispatchEvent: vi.fn(),
+        })),
+      });
+
+      const { unmount } = renderHook(() => usePWA());
+
+      // Capture the registered handler
+      const registeredHandler = addEventListener.mock.calls[0][1];
+
+      unmount();
+
+      expect(removeEventListener).toHaveBeenCalledWith('change', registeredHandler);
+    });
+
+    it('handles multiple mount/unmount cycles correctly', () => {
+      setupPWAMode(false);
+
+      // First mount
+      const { unmount: unmount1 } = renderHook(() => usePWA());
+      unmount1();
+
+      // Second mount (should not cause errors)
+      const { result: result2, unmount: unmount2 } = renderHook(() => usePWA());
+      expect(result2.current).toBe(false);
+      unmount2();
+
+      // Third mount with PWA enabled
+      setupPWAMode(true);
+      const { result: result3 } = renderHook(() => usePWA());
+      expect(result3.current).toBe(true);
+    });
+  });
+
+  describe('Display Mode Changes', () => {
+    it('updates state when display-mode changes', () => {
+      let matchesValue = false;
+      const listeners: Array<() => void> = [];
+
+      Object.defineProperty(window, 'matchMedia', {
+        writable: true,
+        configurable: true,
+        value: vi.fn().mockImplementation(() => ({
+          get matches() {
+            return matchesValue;
+          },
+          media: '(display-mode: standalone)',
+          addEventListener: vi.fn((event: string, handler: () => void) => {
+            listeners.push(handler);
+          }),
+          removeEventListener: vi.fn(),
+          addListener: vi.fn(),
+          removeListener: vi.fn(),
+          dispatchEvent: vi.fn(),
+        })),
+      });
+
+      const { result, rerender } = renderHook(() => usePWA());
+
+      // Initially not in PWA mode
+      expect(result.current).toBe(false);
+
+      // Simulate entering PWA mode
+      act(() => {
+        matchesValue = true;
+        // Trigger the change event
+        listeners.forEach(handler => handler());
+      });
+      rerender();
+
+      // Should now detect PWA mode
+      expect(result.current).toBe(true);
+    });
+
+    it('updates state when exiting PWA mode', () => {
+      let matchesValue = true;
+      const listeners: Array<() => void> = [];
+
+      Object.defineProperty(window, 'matchMedia', {
+        writable: true,
+        configurable: true,
+        value: vi.fn().mockImplementation(() => ({
+          get matches() {
+            return matchesValue;
+          },
+          media: '(display-mode: standalone)',
+          addEventListener: vi.fn((event: string, handler: () => void) => {
+            listeners.push(handler);
+          }),
+          removeEventListener: vi.fn(),
+          addListener: vi.fn(),
+          removeListener: vi.fn(),
+          dispatchEvent: vi.fn(),
+        })),
+      });
+
+      const { result, rerender } = renderHook(() => usePWA());
+
+      // Initially in PWA mode
+      expect(result.current).toBe(true);
+
+      // Simulate exiting PWA mode
+      act(() => {
+        matchesValue = false;
+        // Trigger the change event
+        listeners.forEach(handler => handler());
+      });
+      rerender();
+
+      // Should now detect non-PWA mode
+      expect(result.current).toBe(false);
+    });
+  });
+
+  describe('Edge Cases', () => {
+    it('handles missing navigator.standalone gracefully', () => {
+      // Setup matchMedia to return false
+      setupPWAMode(false);
+
+      // Ensure navigator.standalone is undefined
+      const originalStandalone = (window.navigator as any).standalone;
+      delete (window.navigator as any).standalone;
+
+      const { result } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(false);
+
+      // Restore original value if it existed
+      if (originalStandalone !== undefined) {
+        (window.navigator as any).standalone = originalStandalone;
+      }
+    });
+  });
+
+  describe('Consistency', () => {
+    it('returns the same value on re-renders if conditions unchanged', () => {
+      setupPWAMode(true);
+
+      const { result, rerender } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(true);
+
+      // Re-render multiple times
+      rerender();
+      expect(result.current).toBe(true);
+
+      rerender();
+      expect(result.current).toBe(true);
+    });
+
+    it('maintains state across re-renders', () => {
+      setupPWAMode(false);
+
+      const { result, rerender } = renderHook(() => usePWA());
+
+      expect(result.current).toBe(false);
+
+      rerender();
+      expect(result.current).toBe(false);
+    });
+  });
+});
diff --git a/frontend/src/test/pwa-test-utils.ts b/frontend/src/test/pwa-test-utils.ts
new file mode 100644
index 0000000..1962ede
--- /dev/null
+++ b/frontend/src/test/pwa-test-utils.ts
@@ -0,0 +1,98 @@
+import { vi } from 'vitest';
+
+/**
+ * Creates a matchMedia mock that can be configured for different query responses
+ * @param standaloneMode - Whether to simulate PWA standalone mode
+ * @returns Mock implementation of window.matchMedia
+ */
+export const createMatchMediaMock = (standaloneMode: boolean = false) => {
+  return vi.fn().mockImplementation((query: string) => ({
+    matches: query.includes('standalone') ? standaloneMode : false,
+    media: query,
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
+    addListener: vi.fn(), // Deprecated but still supported
+    removeListener: vi.fn(), // Deprecated but still supported
+    dispatchEvent: vi.fn(),
+  }));
+};
+
+/**
+ * Sets up window.matchMedia to simulate PWA standalone mode
+ * @param enabled - Whether PWA mode should be enabled (default: true)
+ */
+export const setupPWAMode = (enabled: boolean = true) => {
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    configurable: true,
+    value: createMatchMediaMock(enabled),
+  });
+};
+
+/**
+ * Sets up iOS-specific PWA detection via navigator.standalone
+ * @param enabled - Whether iOS PWA mode should be enabled (default: true)
+ */
+export const setupIOSPWAMode = (enabled: boolean = true) => {
+  Object.defineProperty(window.navigator, 'standalone', {
+    writable: true,
+    configurable: true,
+    value: enabled,
+  });
+};
+
+/**
+ * Resets PWA-related window properties to their default state
+ * Useful for cleanup between tests
+ */
+export const resetPWAMocks = () => {
+  // Reset matchMedia to default non-PWA state
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    configurable: true,
+    value: createMatchMediaMock(false),
+  });
+
+  // Reset iOS standalone if it exists
+  if ('standalone' in window.navigator) {
+    Object.defineProperty(window.navigator, 'standalone', {
+      writable: true,
+      configurable: true,
+      value: undefined,
+    });
+  }
+};
+
+/**
+ * Creates a matchMedia mock that supports multiple query patterns
+ * @param queries - Map of query patterns to their match states
+ * @returns Mock implementation that responds to different queries
+ *
+ * @example
+ * ```typescript
+ * const mockFn = createResponsiveMatchMediaMock({
+ *   'standalone': true,  // PWA mode
+ *   'max-width: 900px': true,  // Mobile
+ * });
+ * ```
+ */
+export const createResponsiveMatchMediaMock = (
+  queries: Record<string, boolean>
+) => {
+  return vi.fn().mockImplementation((query: string) => {
+    // Check if any of the query patterns match the input query
+    const matches = Object.entries(queries).some(([pattern, shouldMatch]) =>
+      query.includes(pattern) ? shouldMatch : false
+    );
+
+    return {
+      matches,
+      media: query,
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+      addListener: vi.fn(),
+      removeListener: vi.fn(),
+      dispatchEvent: vi.fn(),
+    };
+  });
+};
diff --git a/frontend/src/test/test-utils.tsx b/frontend/src/test/test-utils.tsx
index 0bb3879..206903d 100644
--- a/frontend/src/test/test-utils.tsx
+++ b/frontend/src/test/test-utils.tsx
@@ -6,6 +6,7 @@ import { I18nextProvider } from 'react-i18next'
 import i18n from 'i18next'
 import { initReactI18next } from 'react-i18next'
 import { NotificationProvider } from '../contexts/NotificationContext'
+import { createMatchMediaMock, createResponsiveMatchMediaMock } from './pwa-test-utils'
 
 // Initialize i18n for tests
 i18n
@@ -246,6 +247,77 @@ export const renderWithAdminUser = (
   return renderWithAuthenticatedUser(ui, createMockAdminUser(), options)
 }
 
+/**
+ * Renders component with PWA mode enabled
+ * Sets up window.matchMedia to simulate standalone display mode
+ */
+export const renderWithPWA = (
+  ui: React.ReactElement,
+  options?: Omit<RenderOptions, 'wrapper'> & {
+    authValues?: Partial<MockAuthContextType>
+    routerProps?: any
+  }
+) => {
+  // Set up matchMedia to return true for standalone mode
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    configurable: true,
+    value: createMatchMediaMock(true),
+  })
+
+  return renderWithProviders(ui, options)
+}
+
+/**
+ * Renders component with mobile viewport simulation
+ * Mocks useMediaQuery to return true for mobile breakpoints
+ */
+export const renderWithMobile = (
+  ui: React.ReactElement,
+  options?: Omit<RenderOptions, 'wrapper'> & {
+    authValues?: Partial<MockAuthContextType>
+    routerProps?: any
+  }
+) => {
+  // Set up matchMedia to simulate mobile viewport (max-width: 900px)
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    configurable: true,
+    value: createResponsiveMatchMediaMock({
+      '(max-width: 900px)': true,
+      '(max-width:900px)': true, // Without spaces variant
+    }),
+  })
+
+  return renderWithProviders(ui, options)
+}
+
+/**
+ * Renders component with both PWA mode and mobile viewport
+ * Combines PWA standalone mode with mobile breakpoint simulation
+ */
+export const renderWithPWAMobile = (
+  ui: React.ReactElement,
+  options?: Omit<RenderOptions, 'wrapper'> & {
+    authValues?: Partial<MockAuthContextType>
+    routerProps?: any
+  }
+) => {
+  // Set up matchMedia to handle both PWA and mobile queries
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    configurable: true,
+    value: createResponsiveMatchMediaMock({
+      'standalone': true,
+      '(display-mode: standalone)': true,
+      '(max-width: 900px)': true,
+      '(max-width:900px)': true,
+    }),
+  })
+
+  return renderWithProviders(ui, options)
+}
+
 // Mock localStorage consistently across tests
 export const createMockLocalStorage = () => {
   const storage: Record<string, string> = {}