diff --git a/docs/progress.md b/docs/progress.md
index d13b72f..ba99d82 100644
--- a/docs/progress.md
+++ b/docs/progress.md
@@ -2,6 +2,33 @@
 
 Updated: 2026-02-15
 
+## Latest Milestone (2026-02-15): Auth Session UX
+
+Implemented app-level authentication/session flow so navigation is now session-aware:
+
+- Added session lifecycle controller:
+  - `lib/features/auth/session_controller.dart`
+  - bootstraps from token store on app startup
+  - supports sign-in, sign-out, and profile refresh
+  - enforces offline-safe sign-out (always clears local session)
+- Added sign-in experience:
+  - `lib/features/auth/sign_in_view.dart`
+  - supports Password / Magic Link / OIDC request shapes
+  - shows mode status (Fake/REST)
+- Updated app bootstrap:
+  - `lib/main.dart` now gates between `SignInView` and `AppShell` based on session state
+- Updated settings with session actions:
+  - `lib/features/settings/settings_view.dart`
+  - shows current identity and provides `Sign Out` + `Refresh Profile`
+- Added auth tests:
+  - `test/features/auth/session_controller_test.dart`
+  - updated `test/widget_test.dart` for sign-in default route
+
+Validation for this milestone:
+
+- `flutter analyze` -> pass
+- `flutter test` -> pass
+
 ## Latest Milestone (2026-02-15): Ideas + Reminders Phase
 
 Implemented the next Phase 2 slice by introducing Ideas and Reminder Rules as first-class local features.
diff --git a/lib/features/auth/session_controller.dart b/lib/features/auth/session_controller.dart
new file mode 100644
index 0000000..28d22c2
--- /dev/null
+++ b/lib/features/auth/session_controller.dart
@@ -0,0 +1,76 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:relationship_saver/core/auth/token_store.dart';
+import 'package:relationship_saver/integrations/backend/backend_gateway.dart';
+import 'package:relationship_saver/integrations/backend/backend_gateway_provider.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
+
+/// Manages authenticated session lifecycle for app-level navigation.
+class SessionController extends AsyncNotifier<AuthSession?> {
+  @override
+  Future<AuthSession?> build() async {
+    return ref.read(tokenStoreProvider).read();
+  }
+
+  Future<void> signIn({
+    required SignInMethod method,
+    String? email,
+    String? password,
+    String? idToken,
+  }) async {
+    state = const AsyncLoading<AuthSession?>();
+
+    try {
+      final BackendGateway gateway = ref.read(backendGatewayProvider);
+      final AuthSession session = await gateway.signIn(
+        SignInRequest(
+          method: method,
+          email: email,
+          password: password,
+          idToken: idToken,
+        ),
+      );
+
+      // Ensure fake gateway sessions are also persisted.
+      await ref.read(tokenStoreProvider).write(session);
+      state = AsyncData<AuthSession?>(session);
+    } catch (error, stackTrace) {
+      state = AsyncError<AuthSession?>(error, stackTrace);
+    }
+  }
+
+  Future<void> signOut() async {
+    final BackendGateway gateway = ref.read(backendGatewayProvider);
+    final TokenStore tokenStore = ref.read(tokenStoreProvider);
+
+    try {
+      await gateway.signOut();
+    } catch (_) {
+      // Offline-first sign-out should always clear local session.
+    }
+
+    await tokenStore.clear();
+    state = const AsyncData<AuthSession?>(null);
+  }
+
+  Future<void> refreshProfile() async {
+    final AuthSession? current = state.asData?.value;
+    if (current == null) {
+      return;
+    }
+
+    try {
+      final UserProfile profile = await ref.read(backendGatewayProvider).me();
+      final AuthSession updated = current.copyWith(user: profile);
+      await ref.read(tokenStoreProvider).write(updated);
+      state = AsyncData<AuthSession?>(updated);
+    } catch (_) {
+      // Keep current state if profile refresh fails.
+    }
+  }
+}
+
+final AsyncNotifierProvider<SessionController, AuthSession?>
+sessionControllerProvider =
+    AsyncNotifierProvider<SessionController, AuthSession?>(
+      SessionController.new,
+    );
diff --git a/lib/features/auth/sign_in_view.dart b/lib/features/auth/sign_in_view.dart
new file mode 100644
index 0000000..c6d0580
--- /dev/null
+++ b/lib/features/auth/sign_in_view.dart
@@ -0,0 +1,176 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:relationship_saver/core/config/app_config.dart';
+import 'package:relationship_saver/core/config/app_theme.dart';
+import 'package:relationship_saver/features/auth/session_controller.dart';
+import 'package:relationship_saver/features/shared/frosted_card.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
+
+class SignInView extends ConsumerStatefulWidget {
+  const SignInView({super.key});
+
+  @override
+  ConsumerState<SignInView> createState() => _SignInViewState();
+}
+
+class _SignInViewState extends ConsumerState<SignInView> {
+  SignInMethod _method = SignInMethod.password;
+  final TextEditingController _emailController = TextEditingController(
+    text: 'demo@example.com',
+  );
+  final TextEditingController _passwordController = TextEditingController(
+    text: 'password123',
+  );
+  final TextEditingController _idTokenController = TextEditingController();
+
+  @override
+  void dispose() {
+    _emailController.dispose();
+    _passwordController.dispose();
+    _idTokenController.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final AsyncValue<AuthSession?> session = ref.watch(
+      sessionControllerProvider,
+    );
+    final bool busy = session.isLoading;
+    final Object? error = session.asError?.error;
+
+    return Center(
+      child: ConstrainedBox(
+        constraints: const BoxConstraints(maxWidth: 620),
+        child: Padding(
+          padding: const EdgeInsets.all(24),
+          child: FrostedCard(
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: <Widget>[
+                Text(
+                  'Sign in to continue',
+                  style: Theme.of(context).textTheme.headlineMedium,
+                ),
+                const SizedBox(height: 8),
+                Text(
+                  'Your local data remains available offline. Backend unlocks sync and signals.',
+                  style: Theme.of(context).textTheme.bodyLarge?.copyWith(
+                    color: AppTheme.textSecondary,
+                  ),
+                ),
+                const SizedBox(height: 18),
+                SegmentedButton<SignInMethod>(
+                  segments: const <ButtonSegment<SignInMethod>>[
+                    ButtonSegment<SignInMethod>(
+                      value: SignInMethod.password,
+                      label: Text('Password'),
+                    ),
+                    ButtonSegment<SignInMethod>(
+                      value: SignInMethod.emailMagicLink,
+                      label: Text('Magic Link'),
+                    ),
+                    ButtonSegment<SignInMethod>(
+                      value: SignInMethod.oidc,
+                      label: Text('OIDC'),
+                    ),
+                  ],
+                  selected: <SignInMethod>{_method},
+                  onSelectionChanged: busy
+                      ? null
+                      : (Set<SignInMethod> value) {
+                          setState(() {
+                            _method = value.first;
+                          });
+                        },
+                ),
+                const SizedBox(height: 14),
+                if (_method == SignInMethod.password ||
+                    _method == SignInMethod.emailMagicLink)
+                  TextField(
+                    controller: _emailController,
+                    keyboardType: TextInputType.emailAddress,
+                    enabled: !busy,
+                    decoration: const InputDecoration(labelText: 'Email'),
+                  ),
+                if (_method == SignInMethod.password)
+                  TextField(
+                    controller: _passwordController,
+                    obscureText: true,
+                    enabled: !busy,
+                    decoration: const InputDecoration(labelText: 'Password'),
+                  ),
+                if (_method == SignInMethod.oidc)
+                  TextField(
+                    controller: _idTokenController,
+                    enabled: !busy,
+                    decoration: const InputDecoration(labelText: 'ID Token'),
+                  ),
+                if (error != null)
+                  Padding(
+                    padding: const EdgeInsets.only(top: 10),
+                    child: Text(
+                      'Sign-in failed: $error',
+                      style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                        color: const Color(0xFFC83030),
+                      ),
+                    ),
+                  ),
+                const SizedBox(height: 16),
+                Row(
+                  children: <Widget>[
+                    FilledButton.icon(
+                      onPressed: busy ? null : _submit,
+                      icon: busy
+                          ? const SizedBox(
+                              width: 16,
+                              height: 16,
+                              child: CircularProgressIndicator(
+                                strokeWidth: 2,
+                                color: Colors.white,
+                              ),
+                            )
+                          : const Icon(Icons.login_rounded),
+                      label: const Text('Sign In'),
+                    ),
+                    const SizedBox(width: 12),
+                    Text(
+                      AppConfig.useFakeBackend
+                          ? 'Fake mode enabled'
+                          : 'REST mode (${AppConfig.backendBaseUrl})',
+                      style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                        color: AppTheme.textSecondary,
+                      ),
+                    ),
+                  ],
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  Future<void> _submit() async {
+    final String? email = _emailController.text.trim().isEmpty
+        ? null
+        : _emailController.text.trim();
+    final String? password = _passwordController.text.trim().isEmpty
+        ? null
+        : _passwordController.text.trim();
+    final String? idToken = _idTokenController.text.trim().isEmpty
+        ? null
+        : _idTokenController.text.trim();
+
+    await ref
+        .read(sessionControllerProvider.notifier)
+        .signIn(
+          method: _method,
+          email: email,
+          password: password,
+          idToken: idToken,
+        );
+  }
+}
diff --git a/lib/features/settings/settings_view.dart b/lib/features/settings/settings_view.dart
index bc2668a..87babae 100644
--- a/lib/features/settings/settings_view.dart
+++ b/lib/features/settings/settings_view.dart
@@ -1,13 +1,21 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:relationship_saver/core/config/app_config.dart';
 import 'package:relationship_saver/core/config/app_theme.dart';
+import 'package:relationship_saver/features/auth/session_controller.dart';
 import 'package:relationship_saver/features/shared/frosted_card.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
 
-class SettingsView extends StatelessWidget {
+class SettingsView extends ConsumerWidget {
   const SettingsView({super.key});
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final AuthSession? session = ref
+        .watch(sessionControllerProvider)
+        .asData
+        ?.value;
+
     return Padding(
       padding: const EdgeInsets.fromLTRB(28, 24, 28, 28),
       child: Column(
@@ -26,6 +34,14 @@ class SettingsView extends StatelessWidget {
             child: Column(
               crossAxisAlignment: CrossAxisAlignment.start,
               children: <Widget>[
+                _SettingRow(
+                  label: 'Signed in as',
+                  value:
+                      session?.user.email ??
+                      session?.user.id ??
+                      'Not signed in',
+                ),
+                const SizedBox(height: 12),
                 _SettingRow(
                   label: 'Gateway mode',
                   value: AppConfig.useFakeBackend
@@ -39,6 +55,30 @@ class SettingsView extends StatelessWidget {
                   label: 'Realtime',
                   value: 'Planned later (SSE/WebSocket)',
                 ),
+                const SizedBox(height: 14),
+                Row(
+                  children: <Widget>[
+                    FilledButton.icon(
+                      onPressed: session == null
+                          ? null
+                          : () => _signOut(context, ref),
+                      icon: const Icon(Icons.logout_rounded),
+                      label: const Text('Sign Out'),
+                    ),
+                    const SizedBox(width: 8),
+                    OutlinedButton.icon(
+                      onPressed: session == null
+                          ? null
+                          : () {
+                              ref
+                                  .read(sessionControllerProvider.notifier)
+                                  .refreshProfile();
+                            },
+                      icon: const Icon(Icons.refresh_rounded),
+                      label: const Text('Refresh Profile'),
+                    ),
+                  ],
+                ),
               ],
             ),
           ),
@@ -53,6 +93,15 @@ class SettingsView extends StatelessWidget {
       ),
     );
   }
+
+  Future<void> _signOut(BuildContext context, WidgetRef ref) async {
+    await ref.read(sessionControllerProvider.notifier).signOut();
+    if (context.mounted) {
+      ScaffoldMessenger.of(
+        context,
+      ).showSnackBar(const SnackBar(content: Text('Signed out.')));
+    }
+  }
 }
 
 class _SettingRow extends StatelessWidget {
diff --git a/lib/main.dart b/lib/main.dart
index c6e0e68..1b705ac 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -1,22 +1,36 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:relationship_saver/core/config/app_theme.dart';
+import 'package:relationship_saver/features/auth/session_controller.dart';
+import 'package:relationship_saver/features/auth/sign_in_view.dart';
 import 'package:relationship_saver/features/home/app_shell.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
 
 void main() {
   runApp(const ProviderScope(child: RelationshipSaverApp()));
 }
 
-class RelationshipSaverApp extends StatelessWidget {
+class RelationshipSaverApp extends ConsumerWidget {
   const RelationshipSaverApp({super.key});
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final AsyncValue<AuthSession?> sessionState = ref.watch(
+      sessionControllerProvider,
+    );
+
     return MaterialApp(
       title: 'Relationship Saver',
       debugShowCheckedModeBanner: false,
       theme: AppTheme.light(),
-      home: const AppShell(),
+      home: Scaffold(
+        body: sessionState.when(
+          data: (session) =>
+              session == null ? const SignInView() : const AppShell(),
+          loading: () => const Center(child: CircularProgressIndicator()),
+          error: (Object error, StackTrace stackTrace) => const SignInView(),
+        ),
+      ),
     );
   }
 }
diff --git a/test/features/auth/session_controller_test.dart b/test/features/auth/session_controller_test.dart
new file mode 100644
index 0000000..e9b7551
--- /dev/null
+++ b/test/features/auth/session_controller_test.dart
@@ -0,0 +1,59 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:relationship_saver/core/auth/in_memory_token_store.dart';
+import 'package:relationship_saver/features/auth/session_controller.dart';
+import 'package:relationship_saver/integrations/backend/backend_gateway_fake.dart';
+import 'package:relationship_saver/integrations/backend/backend_gateway_provider.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
+
+void main() {
+  test('initial state is signed out when token store is empty', () async {
+    final ProviderContainer container = ProviderContainer(
+      overrides: [
+        tokenStoreProvider.overrideWithValue(InMemoryTokenStore()),
+        backendGatewayProvider.overrideWithValue(BackendGatewayFake()),
+      ],
+    );
+    addTearDown(container.dispose);
+
+    final AuthSession? session = await container.read(
+      sessionControllerProvider.future,
+    );
+    expect(session, isNull);
+  });
+
+  test('sign-in creates session and sign-out clears it', () async {
+    final InMemoryTokenStore tokenStore = InMemoryTokenStore();
+    final ProviderContainer container = ProviderContainer(
+      overrides: [
+        tokenStoreProvider.overrideWithValue(tokenStore),
+        backendGatewayProvider.overrideWithValue(BackendGatewayFake()),
+      ],
+    );
+    addTearDown(container.dispose);
+
+    await container
+        .read(sessionControllerProvider.notifier)
+        .signIn(
+          method: SignInMethod.password,
+          email: 'demo@example.com',
+          password: 'password123',
+        );
+
+    final AuthSession? signedIn = container
+        .read(sessionControllerProvider)
+        .asData
+        ?.value;
+    expect(signedIn, isNotNull);
+    expect(signedIn?.user.email, 'demo@example.com');
+
+    await container.read(sessionControllerProvider.notifier).signOut();
+
+    final AuthSession? signedOut = container
+        .read(sessionControllerProvider)
+        .asData
+        ?.value;
+    expect(signedOut, isNull);
+    expect(await tokenStore.read(), isNull);
+  });
+}
diff --git a/test/widget_test.dart b/test/widget_test.dart
index e47e0ce..3f936ce 100644
--- a/test/widget_test.dart
+++ b/test/widget_test.dart
@@ -1,5 +1,7 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:relationship_saver/core/auth/in_memory_token_store.dart';
+import 'package:relationship_saver/integrations/backend/backend_gateway_provider.dart';
 import 'package:relationship_saver/main.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -8,11 +10,16 @@ void main() {
     SharedPreferences.setMockInitialValues(<String, Object>{});
   });
 
-  testWidgets('renders dashboard flow', (WidgetTester tester) async {
-    await tester.pumpWidget(const ProviderScope(child: RelationshipSaverApp()));
+  testWidgets('renders sign-in flow by default', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      ProviderScope(
+        overrides: [tokenStoreProvider.overrideWithValue(InMemoryTokenStore())],
+        child: const RelationshipSaverApp(),
+      ),
+    );
     await tester.pumpAndSettle();
 
-    expect(find.text('Today'), findsOneWidget);
-    expect(find.text('Active People'), findsOneWidget);
+    expect(find.text('Sign in to continue'), findsOneWidget);
+    expect(find.text('Sign In'), findsOneWidget);
   });
 }