diff --git a/android/app/src/main/AndroidManifest.xml b/android/app/src/main/AndroidManifest.xml
index 5beb08c..c7d3028 100644
--- a/android/app/src/main/AndroidManifest.xml
+++ b/android/app/src/main/AndroidManifest.xml
@@ -13,6 +13,7 @@
     <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
     
     <!-- Permissions pour écrire dans le stockage -->
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <application
         android:label="Travel Mate"
@@ -62,6 +63,9 @@
         <meta-data
             android:name="com.google.android.geo.API_KEY"
             android:value="AIzaSyCAtz1_d5K0ANwxAA_T84iq7Ac_gsUs_oM"/>
+        <meta-data
+            android:name="com.google.firebase.messaging.default_notification_channel_id"
+            android:value="high_importance_channel" />
     </application>
     <!-- Required to query activities that can process text, see:
          https://developer.android.com/training/package-visibility and
diff --git a/functions/index.js b/functions/index.js
index f8c0703..018a469 100644
--- a/functions/index.js
+++ b/functions/index.js
@@ -5,21 +5,32 @@ admin.initializeApp();
 
 // Helper function to send notifications to a list of users
 async function sendNotificationToUsers(userIds, title, body, excludeUserId, data = {}) {
+    console.log(`Starting sendNotificationToUsers. Total users: ${userIds.length}, Exclude: ${excludeUserId}`);
     try {
         const tokens = [];
 
         for (const userId of userIds) {
-            if (userId === excludeUserId) continue;
+            if (userId === excludeUserId) {
+                console.log(`Skipping user ${userId} (sender)`);
+                continue;
+            }
 
             const userDoc = await admin.firestore().collection("users").doc(userId).get();
             if (userDoc.exists) {
                 const userData = userDoc.data();
                 if (userData.fcmToken) {
+                    console.log(`Found token for user ${userId}`);
                     tokens.push(userData.fcmToken);
+                } else {
+                    console.log(`No FCM token found for user ${userId}`);
                 }
+            } else {
+                console.log(`User document not found for ${userId}`);
             }
         }
 
+        console.log(`Total tokens to send: ${tokens.length}`);
+
         if (tokens.length > 0) {
             const message = {
                 notification: {
@@ -35,6 +46,11 @@ async function sendNotificationToUsers(userIds, title, body, excludeUserId, data
 
             const response = await admin.messaging().sendMulticast(message);
             console.log(`${response.successCount} messages were sent successfully`);
+            if (response.failureCount > 0) {
+                console.log('Failed notifications:', response.responses.filter(r => !r.success));
+            }
+        } else {
+            console.log("No tokens found, skipping notification send.");
         }
     } catch (error) {
         console.error("Error sending notification:", error);
@@ -44,6 +60,7 @@ async function sendNotificationToUsers(userIds, title, body, excludeUserId, data
 exports.onActivityCreated = functions.firestore
     .document("activities/{activityId}")
     .onCreate(async (snapshot, context) => {
+        console.log(`onActivityCreated triggered for ${context.params.activityId}`);
         const activity = snapshot.data();
         const tripId = activity.tripId;
         const createdBy = activity.createdBy || "Unknown";
@@ -66,6 +83,8 @@ exports.onActivityCreated = functions.firestore
             participants.push(trip.createdBy);
         }
 
+        console.log(`Found trip participants: ${JSON.stringify(participants)}`);
+
         // Fetch creator name
         let creatorName = "Quelqu'un";
         if (createdBy !== "Unknown") {
@@ -87,6 +106,7 @@ exports.onActivityCreated = functions.firestore
 exports.onMessageCreated = functions.firestore
     .document("groups/{groupId}/messages/{messageId}")
     .onCreate(async (snapshot, context) => {
+        console.log(`onMessageCreated triggered for ${context.params.messageId} in group ${context.params.groupId}`);
         const message = snapshot.data();
         const groupId = context.params.groupId;
         const senderId = message.senderId;
@@ -100,6 +120,7 @@ exports.onMessageCreated = functions.firestore
 
         const group = groupDoc.data();
         const memberIds = group.memberIds || [];
+        console.log(`Found group members: ${JSON.stringify(memberIds)}`);
 
         let senderName = message.senderName || "Quelqu'un";
 
@@ -115,6 +136,7 @@ exports.onMessageCreated = functions.firestore
 exports.onExpenseCreated = functions.firestore
     .document("expenses/{expenseId}")
     .onCreate(async (snapshot, context) => {
+        console.log(`onExpenseCreated triggered for ${context.params.expenseId}`);
         const expense = snapshot.data();
         const groupId = expense.groupId;
         const paidBy = expense.paidById || expense.paidBy;
@@ -133,6 +155,7 @@ exports.onExpenseCreated = functions.firestore
 
         const group = groupDoc.data();
         const memberIds = group.memberIds || [];
+        console.log(`Found group members: ${JSON.stringify(memberIds)}`);
 
         let payerName = expense.paidByName || "Quelqu'un";
 
diff --git a/lib/blocs/auth/auth_bloc.dart b/lib/blocs/auth/auth_bloc.dart
index 4159abb..5c86dfd 100644
--- a/lib/blocs/auth/auth_bloc.dart
+++ b/lib/blocs/auth/auth_bloc.dart
@@ -25,6 +25,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import '../../repositories/auth_repository.dart';
 import 'auth_event.dart';
 import 'auth_state.dart';
+import '../../services/notification_service.dart';
 
 /// BLoC for managing authentication state and operations.
 class AuthBloc extends Bloc<AuthEvent, AuthState> {
@@ -69,6 +70,8 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
         );
 
         if (user != null) {
+          // Save FCM Token on auto-login
+          await NotificationService().saveTokenToFirestore(user.id!);
           emit(AuthAuthenticated(user: user));
         } else {
           emit(AuthUnauthenticated());
@@ -98,6 +101,8 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
       );
 
       if (user != null) {
+        // Save FCM Token
+        await NotificationService().saveTokenToFirestore(user.id!);
         emit(AuthAuthenticated(user: user));
       } else {
         emit(const AuthError(message: 'Invalid email or password'));
@@ -127,6 +132,8 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
       );
 
       if (user != null) {
+        // Save FCM Token
+        await NotificationService().saveTokenToFirestore(user.id!);
         emit(AuthAuthenticated(user: user));
       } else {
         emit(const AuthError(message: 'Failed to create account'));
@@ -150,6 +157,8 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
       final user = await _authRepository.signInWithGoogle();
 
       if (user != null) {
+        // Save FCM Token
+        await NotificationService().saveTokenToFirestore(user.id!);
         emit(AuthAuthenticated(user: user));
       } else {
         emit(
@@ -224,6 +233,8 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
       final user = await _authRepository.signInWithApple();
 
       if (user != null) {
+        // Save FCM Token
+        await NotificationService().saveTokenToFirestore(user.id!);
         emit(AuthAuthenticated(user: user));
       } else {
         emit(
diff --git a/lib/blocs/user/user_bloc.dart b/lib/blocs/user/user_bloc.dart
index 365b824..83d5aec 100644
--- a/lib/blocs/user/user_bloc.dart
+++ b/lib/blocs/user/user_bloc.dart
@@ -86,9 +86,9 @@ class UserBloc extends Bloc<event.UserEvent, state.UserState> {
         // Update FCM token if it changed
         if (fcmToken != null && user.fcmToken != fcmToken) {
           LoggerService.info('UserBloc - Updating FCM token in Firestore');
-          await _firestore.collection('users').doc(currentUser.uid).update({
+          await _firestore.collection('users').doc(currentUser.uid).set({
             'fcmToken': fcmToken,
-          });
+          }, SetOptions(merge: true));
           LoggerService.info('UserBloc - FCM token updated');
         } else {
           LoggerService.info(
diff --git a/lib/components/account/expense_detail_dialog.dart b/lib/components/account/expense_detail_dialog.dart
index c40cf69..bb67516 100644
--- a/lib/components/account/expense_detail_dialog.dart
+++ b/lib/components/account/expense_detail_dialog.dart
@@ -42,185 +42,318 @@ class ExpenseDetailDialog extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     // Formatters for displaying dates and times.
-    final dateFormat = DateFormat('dd MMMM yyyy');
-    final timeFormat = DateFormat('HH:mm');
+    final dateFormat = DateFormat('dd MMMM yyyy', 'fr_FR');
+
+    final theme = Theme.of(context);
 
     return BlocBuilder<UserBloc, user_state.UserState>(
       builder: (context, userState) {
         // Determine the current user and their permissions.
-        final currentUser = userState is user_state.UserLoaded ? userState.user : null;
+        final currentUser = userState is user_state.UserLoaded
+            ? userState.user
+            : null;
         final canEdit = currentUser?.id == expense.paidById;
 
         return Dialog(
+          backgroundColor: Colors.transparent,
+          insetPadding: const EdgeInsets.all(16),
           child: Container(
             constraints: const BoxConstraints(maxWidth: 500, maxHeight: 700),
-            child: Scaffold(
-              appBar: AppBar(
-                title: const Text('Détails de la dépense'),
-                automaticallyImplyLeading: false,
-                actions: [
-                  if (canEdit) ...[
-                    // Edit button.
-                    IconButton(
-                      icon: const Icon(Icons.edit),
-                      onPressed: () {
-                        Navigator.of(context).pop();
-                        _showEditDialog(context, currentUser!);
-                      },
-                    ),
-                    // Delete button.
-                    IconButton(
-                      icon: const Icon(Icons.delete, color: Colors.red),
-                      onPressed: () => _confirmDelete(context),
-                    ),
-                  ],
-                  // Close button.
-                  IconButton(
-                    icon: const Icon(Icons.close),
-                    onPressed: () => Navigator.of(context).pop(),
-                  ),
-                ],
-              ),
-              body: ListView(
-                padding: const EdgeInsets.all(16),
-                children: [
-                  // Header with icon and description.
-                  Center(
-                    child: Column(
-                      children: [
-                        Container(
-                          width: 80,
-                          height: 80,
-                          decoration: BoxDecoration(
-                            color: Colors.blue.withValues(alpha: 0.1),
-                            shape: BoxShape.circle,
+            decoration: BoxDecoration(
+              color: theme.colorScheme.surface,
+              borderRadius: BorderRadius.circular(28),
+              boxShadow: [
+                BoxShadow(
+                  color: Colors.black.withValues(alpha: 0.2),
+                  blurRadius: 20,
+                  offset: const Offset(0, 10),
+                ),
+              ],
+            ),
+            child: Column(
+              children: [
+                // Header with actions
+                Padding(
+                  padding: const EdgeInsets.fromLTRB(24, 20, 16, 0),
+                  child: Row(
+                    children: [
+                      Text(
+                        'Détails',
+                        style: theme.textTheme.titleLarge?.copyWith(
+                          fontWeight: FontWeight.bold,
+                        ),
+                      ),
+                      const Spacer(),
+                      if (canEdit) ...[
+                        IconButton(
+                          icon: const Icon(Icons.edit_outlined),
+                          tooltip: 'Modifier',
+                          onPressed: () {
+                            Navigator.of(context).pop();
+                            _showEditDialog(context, currentUser!);
+                          },
+                        ),
+                        IconButton(
+                          icon: const Icon(
+                            Icons.delete_outline,
+                            color: Colors.red,
                           ),
-                          child: Icon(
-                            expense.category.icon,
-                            size: 40,
-                            color: Colors.blue,
+                          tooltip: 'Supprimer',
+                          onPressed: () => _confirmDelete(context),
+                        ),
+                      ],
+                      IconButton(
+                        icon: const Icon(Icons.close),
+                        onPressed: () => Navigator.of(context).pop(),
+                      ),
+                    ],
+                  ),
+                ),
+
+                Expanded(
+                  child: ListView(
+                    padding: const EdgeInsets.fromLTRB(24, 10, 24, 24),
+                    children: [
+                      // Icon and Category
+                      Center(
+                        child: Column(
+                          children: [
+                            Container(
+                              width: 80,
+                              height: 80,
+                              decoration: BoxDecoration(
+                                color: theme.colorScheme.primaryContainer
+                                    .withValues(alpha: 0.3),
+                                shape: BoxShape.circle,
+                              ),
+                              child: Icon(
+                                expense.category.icon,
+                                size: 36,
+                                color: theme.colorScheme.primary,
+                              ),
+                            ),
+                            const SizedBox(height: 16),
+                            Text(
+                              expense.description,
+                              style: theme.textTheme.headlineSmall?.copyWith(
+                                fontWeight: FontWeight.bold,
+                              ),
+                              textAlign: TextAlign.center,
+                            ),
+                            const SizedBox(height: 4),
+                            Container(
+                              padding: const EdgeInsets.symmetric(
+                                horizontal: 12,
+                                vertical: 6,
+                              ),
+                              decoration: BoxDecoration(
+                                color:
+                                    theme.colorScheme.surfaceContainerHighest,
+                                borderRadius: BorderRadius.circular(20),
+                              ),
+                              child: Text(
+                                expense.category.displayName,
+                                style: theme.textTheme.labelMedium?.copyWith(
+                                  color: theme.colorScheme.onSurfaceVariant,
+                                ),
+                              ),
+                            ),
+                          ],
+                        ),
+                      ),
+                      const SizedBox(height: 32),
+
+                      // Amount Display
+                      Container(
+                        padding: const EdgeInsets.all(24),
+                        decoration: BoxDecoration(
+                          color: theme.colorScheme.surfaceContainerHighest
+                              .withValues(alpha: 0.3),
+                          borderRadius: BorderRadius.circular(24),
+                          border: Border.all(
+                            color: theme.colorScheme.outline.withValues(
+                              alpha: 0.1,
+                            ),
                           ),
                         ),
-                        const SizedBox(height: 16),
+                        child: Column(
+                          children: [
+                            Text(
+                              'Montant total',
+                              style: theme.textTheme.labelLarge?.copyWith(
+                                color: theme.colorScheme.onSurfaceVariant,
+                              ),
+                            ),
+                            const SizedBox(height: 8),
+                            Text(
+                              '${expense.amount.toStringAsFixed(2)} ${expense.currency.symbol}',
+                              style: theme.textTheme.displaySmall?.copyWith(
+                                fontWeight: FontWeight.w800,
+                                color: theme.colorScheme.primary,
+                              ),
+                            ),
+                            if (expense.currency != ExpenseCurrency.eur)
+                              Padding(
+                                padding: const EdgeInsets.only(top: 4),
+                                child: Text(
+                                  '≈ ${expense.amountInEur.toStringAsFixed(2)} €',
+                                  style: theme.textTheme.bodyMedium?.copyWith(
+                                    color: theme.colorScheme.onSurfaceVariant,
+                                  ),
+                                ),
+                              ),
+                          ],
+                        ),
+                      ),
+                      const SizedBox(height: 24),
+
+                      // Info Grid
+                      Row(
+                        children: [
+                          Expanded(
+                            child: _buildInfoCard(
+                              context,
+                              Icons.person_outline,
+                              'Payé par',
+                              expense.paidByName,
+                            ),
+                          ),
+                          const SizedBox(width: 12),
+                          Expanded(
+                            child: _buildInfoCard(
+                              context,
+                              Icons.calendar_today_outlined,
+                              'Date',
+                              dateFormat.format(expense.date),
+                            ),
+                          ),
+                        ],
+                      ),
+                      const SizedBox(height: 24),
+
+                      // Splits Section
+                      Text(
+                        'Répartition',
+                        style: theme.textTheme.titleMedium?.copyWith(
+                          fontWeight: FontWeight.bold,
+                        ),
+                      ),
+                      const SizedBox(height: 12),
+                      Container(
+                        decoration: BoxDecoration(
+                          color: theme.colorScheme.surface,
+                          borderRadius: BorderRadius.circular(16),
+                          border: Border.all(
+                            color: theme.colorScheme.outline.withValues(
+                              alpha: 0.1,
+                            ),
+                          ),
+                        ),
+                        child: Column(
+                          children: expense.splits.asMap().entries.map((entry) {
+                            final index = entry.key;
+                            final split = entry.value;
+                            final isLast = index == expense.splits.length - 1;
+                            return Column(
+                              children: [
+                                _buildSplitTile(context, split),
+                                if (!isLast)
+                                  Divider(
+                                    height: 1,
+                                    indent: 16,
+                                    endIndent: 16,
+                                    color: theme.colorScheme.outline.withValues(
+                                      alpha: 0.1,
+                                    ),
+                                  ),
+                              ],
+                            );
+                          }).toList(),
+                        ),
+                      ),
+
+                      // Receipt Section
+                      if (expense.receiptUrl != null) ...[
+                        const SizedBox(height: 24),
                         Text(
-                          expense.description,
-                          style: const TextStyle(
-                            fontSize: 24,
+                          'Reçu',
+                          style: theme.textTheme.titleMedium?.copyWith(
                             fontWeight: FontWeight.bold,
                           ),
-                          textAlign: TextAlign.center,
                         ),
-                        const SizedBox(height: 8),
-                        Text(
-                          expense.category.displayName,
-                          style: TextStyle(
-                            fontSize: 14,
-                            color: Colors.grey[600],
+                        const SizedBox(height: 12),
+                        ClipRRect(
+                          borderRadius: BorderRadius.circular(16),
+                          child: Stack(
+                            alignment: Alignment.center,
+                            children: [
+                              Image.network(
+                                expense.receiptUrl!,
+                                width: double.infinity,
+                                height: 200,
+                                fit: BoxFit.cover,
+                                loadingBuilder:
+                                    (context, child, loadingProgress) {
+                                      if (loadingProgress == null) return child;
+                                      return Container(
+                                        height: 200,
+                                        color: theme
+                                            .colorScheme
+                                            .surfaceContainerHighest,
+                                        child: const Center(
+                                          child: CircularProgressIndicator(),
+                                        ),
+                                      );
+                                    },
+                                errorBuilder: (context, error, stackTrace) {
+                                  return Container(
+                                    height: 200,
+                                    color: theme
+                                        .colorScheme
+                                        .surfaceContainerHighest,
+                                    child: const Center(
+                                      child: Icon(Icons.broken_image_outlined),
+                                    ),
+                                  );
+                                },
+                              ),
+                              Positioned.fill(
+                                child: Material(
+                                  color: Colors.transparent,
+                                  child: InkWell(
+                                    onTap: () {
+                                      // TODO: Show full screen image
+                                    },
+                                  ),
+                                ),
+                              ),
+                            ],
                           ),
                         ),
                       ],
-                    ),
-                  ),
-                  const SizedBox(height: 24),
 
-                  // Amount card.
-                  Card(
-                    child: Padding(
-                      padding: const EdgeInsets.all(16),
-                      child: Column(
-                        children: [
-                          Text(
-                            '${expense.amount.toStringAsFixed(2)} ${expense.currency.symbol}',
-                            style: const TextStyle(
-                              fontSize: 32,
-                              fontWeight: FontWeight.bold,
-                              color: Colors.green,
-                            ),
-                          ),
-                          if (expense.currency != ExpenseCurrency.eur)
-                            Text(
-                              '≈ ${expense.amountInEur.toStringAsFixed(2)} €',
-                              style: TextStyle(
-                                fontSize: 16,
-                                color: Colors.grey[600],
+                      // Archive Button
+                      if (!expense.isArchived && canEdit) ...[
+                        const SizedBox(height: 32),
+                        SizedBox(
+                          width: double.infinity,
+                          child: OutlinedButton.icon(
+                            onPressed: () => _confirmArchive(context),
+                            icon: const Icon(Icons.archive_outlined),
+                            label: const Text('Archiver cette dépense'),
+                            style: OutlinedButton.styleFrom(
+                              padding: const EdgeInsets.symmetric(vertical: 16),
+                              shape: RoundedRectangleBorder(
+                                borderRadius: BorderRadius.circular(12),
                               ),
                             ),
-                        ],
-                      ),
-                    ),
+                          ),
+                        ),
+                      ],
+                    ],
                   ),
-                  const SizedBox(height: 16),
-
-                  // Information rows.
-                  _buildInfoRow(Icons.person, 'Payé par', expense.paidByName),
-                  _buildInfoRow(Icons.calendar_today, 'Date', dateFormat.format(expense.date)),
-                  _buildInfoRow(Icons.access_time, 'Heure', timeFormat.format(expense.createdAt)),
-
-                  if (expense.isEdited && expense.editedAt != null)
-                    _buildInfoRow(
-                      Icons.edit,
-                      'Modifié le',
-                      dateFormat.format(expense.editedAt!),
-                    ),
-
-                  const SizedBox(height: 16),
-                  const Divider(),
-                  const SizedBox(height: 8),
-
-                  // Splits section.
-                  const Text(
-                    'Répartition',
-                    style: TextStyle(
-                      fontSize: 18,
-                      fontWeight: FontWeight.bold,
-                    ),
-                  ),
-                  const SizedBox(height: 12),
-                  ...expense.splits.map((split) => _buildSplitTile(context, split)),
-
-                  const SizedBox(height: 16),
-
-                  // Receipt section.
-                  if (expense.receiptUrl != null) ...[
-                    const Divider(),
-                    const SizedBox(height: 8),
-                    const Text(
-                      'Reçu',
-                      style: TextStyle(
-                        fontSize: 18,
-                        fontWeight: FontWeight.bold,
-                      ),
-                    ),
-                    const SizedBox(height: 12),
-                    ClipRRect(
-                      borderRadius: BorderRadius.circular(12),
-                      child: Image.network(
-                        expense.receiptUrl!,
-                        fit: BoxFit.cover,
-                        loadingBuilder: (context, child, loadingProgress) {
-                          if (loadingProgress == null) return child;
-                          return const Center(child: CircularProgressIndicator());
-                        },
-                        errorBuilder: (context, error, stackTrace) {
-                          return const Center(
-                            child: Text('Erreur de chargement de l\'image'),
-                          );
-                        },
-                      ),
-                    ),
-                  ],
-
-                  const SizedBox(height: 16),
-
-                  // Archive button.
-                  if (!expense.isArchived && canEdit)
-                    OutlinedButton.icon(
-                      onPressed: () => _confirmArchive(context),
-                      icon: const Icon(Icons.archive),
-                      label: const Text('Archiver cette dépense'),
-                    ),
-                ],
-              ),
+                ),
+              ],
             ),
           ),
         );
@@ -228,83 +361,135 @@ class ExpenseDetailDialog extends StatelessWidget {
     );
   }
 
-  /// Builds a row displaying an icon, a label, and a value.
-  Widget _buildInfoRow(IconData icon, String label, String value) {
-    return Padding(
-      padding: const EdgeInsets.symmetric(vertical: 8),
-      child: Row(
+  Widget _buildInfoCard(
+    BuildContext context,
+    IconData icon,
+    String label,
+    String value,
+  ) {
+    final theme = Theme.of(context);
+    return Container(
+      padding: const EdgeInsets.all(16),
+      decoration: BoxDecoration(
+        color: theme.colorScheme.surface,
+        borderRadius: BorderRadius.circular(16),
+        border: Border.all(
+          color: theme.colorScheme.outline.withValues(alpha: 0.1),
+        ),
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
         children: [
-          Icon(icon, size: 20, color: Colors.grey[600]),
-          const SizedBox(width: 12),
-          Text(
-            label,
-            style: TextStyle(
-              fontSize: 14,
-              color: Colors.grey[600],
-            ),
+          Row(
+            children: [
+              Icon(icon, size: 16, color: theme.colorScheme.onSurfaceVariant),
+              const SizedBox(width: 8),
+              Text(
+                label,
+                style: theme.textTheme.labelMedium?.copyWith(
+                  color: theme.colorScheme.onSurfaceVariant,
+                ),
+              ),
+            ],
           ),
-          const Spacer(),
+          const SizedBox(height: 8),
           Text(
             value,
-            style: const TextStyle(
-              fontSize: 14,
-              fontWeight: FontWeight.w500,
+            style: theme.textTheme.bodyLarge?.copyWith(
+              fontWeight: FontWeight.w600,
             ),
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
           ),
         ],
       ),
     );
   }
 
-  /// Builds a tile displaying details about a split in the expense.
-  ///
-  /// The tile shows the user's name, the split amount, and whether the split is paid. If the current user
-  /// is responsible for the split and it is unpaid, a button is provided to mark it as paid.
   Widget _buildSplitTile(BuildContext context, ExpenseSplit split) {
     return BlocBuilder<UserBloc, user_state.UserState>(
       builder: (context, userState) {
-        final currentUser = userState is user_state.UserLoaded ? userState.user : null;
+        final currentUser = userState is user_state.UserLoaded
+            ? userState.user
+            : null;
         final isCurrentUser = currentUser?.id == split.userId;
+        final theme = Theme.of(context);
 
-        return ListTile(
-          leading: CircleAvatar(
-            backgroundColor: split.isPaid ? Colors.green : Colors.orange,
-            child: Icon(
-              split.isPaid ? Icons.check : Icons.pending,
-              color: Colors.white,
-              size: 20,
-            ),
-          ),
-          title: Text(
-            split.userName,
-            style: TextStyle(
-              fontWeight: isCurrentUser ? FontWeight.bold : FontWeight.normal,
-            ),
-          ),
-          subtitle: Text(split.isPaid ? 'Payé' : 'En attente'),
-          trailing: Row(
-            mainAxisSize: MainAxisSize.min,
+        return Padding(
+          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
+          child: Row(
             children: [
-              Text(
-                '${split.amount.toStringAsFixed(2)} €',
-                style: const TextStyle(
-                  fontSize: 16,
-                  fontWeight: FontWeight.bold,
+              Container(
+                width: 40,
+                height: 40,
+                decoration: BoxDecoration(
+                  color: split.isPaid
+                      ? Colors.green.withValues(alpha: 0.1)
+                      : Colors.orange.withValues(alpha: 0.1),
+                  shape: BoxShape.circle,
+                ),
+                child: Icon(
+                  split.isPaid ? Icons.check : Icons.access_time_rounded,
+                  color: split.isPaid ? Colors.green : Colors.orange,
+                  size: 20,
                 ),
               ),
-              if (!split.isPaid && isCurrentUser) ...[
-                const SizedBox(width: 8),
-                IconButton(
-                  icon: const Icon(Icons.check_circle, color: Colors.green),
-                  onPressed: () {
-                    context.read<ExpenseBloc>().add(MarkSplitAsPaid(
-                      expenseId: expense.id,
-                      userId: split.userId,
-                    ));
-                    Navigator.of(context).pop();
-                  },
+              const SizedBox(width: 12),
+              Expanded(
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    Text(
+                      isCurrentUser ? 'Moi' : split.userName,
+                      style: theme.textTheme.bodyLarge?.copyWith(
+                        fontWeight: isCurrentUser
+                            ? FontWeight.bold
+                            : FontWeight.w500,
+                      ),
+                    ),
+                    Text(
+                      split.isPaid ? 'Payé' : 'En attente',
+                      style: theme.textTheme.bodySmall?.copyWith(
+                        color: split.isPaid ? Colors.green : Colors.orange,
+                        fontWeight: FontWeight.w500,
+                      ),
+                    ),
+                  ],
                 ),
-              ],
+              ),
+              Column(
+                crossAxisAlignment: CrossAxisAlignment.end,
+                children: [
+                  Text(
+                    '${split.amount.toStringAsFixed(2)} €',
+                    style: theme.textTheme.bodyLarge?.copyWith(
+                      fontWeight: FontWeight.bold,
+                    ),
+                  ),
+                  if (!split.isPaid && isCurrentUser)
+                    GestureDetector(
+                      onTap: () {
+                        context.read<ExpenseBloc>().add(
+                          MarkSplitAsPaid(
+                            expenseId: expense.id,
+                            userId: split.userId,
+                          ),
+                        );
+                        Navigator.of(context).pop();
+                      },
+                      child: Padding(
+                        padding: const EdgeInsets.only(top: 4),
+                        child: Text(
+                          'Marquer payé',
+                          style: theme.textTheme.labelSmall?.copyWith(
+                            color: theme.colorScheme.primary,
+                            fontWeight: FontWeight.bold,
+                          ),
+                        ),
+                      ),
+                    ),
+                ],
+              ),
             ],
           ),
         );
@@ -312,7 +497,6 @@ class ExpenseDetailDialog extends StatelessWidget {
     );
   }
 
-  /// Shows a dialog for editing the expense.
   void _showEditDialog(BuildContext context, user_state.UserModel currentUser) {
     showDialog(
       context: context,
@@ -327,13 +511,14 @@ class ExpenseDetailDialog extends StatelessWidget {
     );
   }
 
-  /// Shows a confirmation dialog for deleting the expense.
   void _confirmDelete(BuildContext context) {
     showDialog(
       context: context,
       builder: (dialogContext) => AlertDialog(
         title: const Text('Supprimer la dépense'),
-        content: const Text('Êtes-vous sûr de vouloir supprimer cette dépense ?'),
+        content: const Text(
+          'Êtes-vous sûr de vouloir supprimer cette dépense ?',
+        ),
         actions: [
           TextButton(
             onPressed: () => Navigator.of(dialogContext).pop(),
@@ -341,9 +526,7 @@ class ExpenseDetailDialog extends StatelessWidget {
           ),
           TextButton(
             onPressed: () {
-              context.read<ExpenseBloc>().add(DeleteExpense(
-                expense.id,
-              ));
+              context.read<ExpenseBloc>().add(DeleteExpense(expense.id));
               Navigator.of(dialogContext).pop();
               Navigator.of(context).pop();
             },
@@ -355,13 +538,14 @@ class ExpenseDetailDialog extends StatelessWidget {
     );
   }
 
-  /// Shows a confirmation dialog for archiving the expense.
   void _confirmArchive(BuildContext context) {
     showDialog(
       context: context,
       builder: (dialogContext) => AlertDialog(
         title: const Text('Archiver la dépense'),
-        content: const Text('Cette dépense sera archivée et n\'apparaîtra plus dans les calculs de balance.'),
+        content: const Text(
+          'Cette dépense sera archivée et n\'apparaîtra plus dans les calculs de balance.',
+        ),
         actions: [
           TextButton(
             onPressed: () => Navigator.of(dialogContext).pop(),
@@ -369,9 +553,7 @@ class ExpenseDetailDialog extends StatelessWidget {
           ),
           TextButton(
             onPressed: () {
-              context.read<ExpenseBloc>().add(ArchiveExpense(
-                expense.id,
-              ));
+              context.read<ExpenseBloc>().add(ArchiveExpense(expense.id));
               Navigator.of(dialogContext).pop();
               Navigator.of(context).pop();
             },
diff --git a/lib/components/activities/activities_page.dart b/lib/components/activities/activities_page.dart
index e18467e..41441a0 100644
--- a/lib/components/activities/activities_page.dart
+++ b/lib/components/activities/activities_page.dart
@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:firebase_auth/firebase_auth.dart';
 import '../../blocs/activity/activity_bloc.dart';
 import '../../blocs/activity/activity_event.dart';
 import '../../blocs/activity/activity_state.dart';
@@ -1030,6 +1031,7 @@ class _ActivitiesPageState extends State<ActivitiesPage>
       tripId: widget.trip.id,
       // Générer un nouvel ID unique pour cette activité dans le voyage
       id: DateTime.now().millisecondsSinceEpoch.toString(),
+      createdBy: FirebaseAuth.instance.currentUser?.uid,
     );
 
     // Afficher le LoadingContent avec la tâche d'ajout
diff --git a/lib/components/activities/add_activity_bottom_sheet.dart b/lib/components/activities/add_activity_bottom_sheet.dart
index ca2f39d..a55cd1a 100644
--- a/lib/components/activities/add_activity_bottom_sheet.dart
+++ b/lib/components/activities/add_activity_bottom_sheet.dart
@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:firebase_auth/firebase_auth.dart';
 import 'dart:math' as math;
 import '../../blocs/activity/activity_bloc.dart';
 import '../../blocs/activity/activity_event.dart';
@@ -368,6 +369,7 @@ class _AddActivityBottomSheetState extends State<AddActivityBottomSheet> {
         votes: {},
         createdAt: DateTime.now(),
         updatedAt: DateTime.now(),
+        createdBy: FirebaseAuth.instance.currentUser?.uid,
       );
 
       context.read<ActivityBloc>().add(AddActivity(activity));
diff --git a/lib/main.dart b/lib/main.dart
index 17d09e9..1ea6c56 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -11,6 +11,8 @@ import 'package:travel_mate/services/error_service.dart';
 import 'package:travel_mate/services/activity_places_service.dart';
 import 'package:flutter_dotenv/flutter_dotenv.dart';
 import 'package:travel_mate/services/expense_service.dart';
+import 'package:firebase_messaging/firebase_messaging.dart';
+import 'package:travel_mate/services/notification_service.dart';
 import 'blocs/auth/auth_bloc.dart';
 import 'blocs/auth/auth_event.dart';
 import 'blocs/theme/theme_bloc.dart';
@@ -34,6 +36,8 @@ import 'pages/home.dart';
 import 'pages/signup.dart';
 import 'pages/resetpswd.dart';
 
+import 'package:intl/date_symbol_data_local.dart';
+
 /// Entry point of the Travel Mate application.
 ///
 /// This function initializes Flutter widgets, loads environment variables,
@@ -42,6 +46,12 @@ void main() async {
   WidgetsFlutterBinding.ensureInitialized();
   await dotenv.load(fileName: ".env");
   await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
+  await initializeDateFormatting('fr_FR', null);
+
+  // Set the background messaging handler early on, as a named top-level function
+  FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);
+
+  await NotificationService().initialize();
 
   runApp(const MyApp());
 }
diff --git a/lib/models/activity.dart b/lib/models/activity.dart
index 272bb45..f44e9a6 100644
--- a/lib/models/activity.dart
+++ b/lib/models/activity.dart
@@ -21,6 +21,7 @@ class Activity {
   final DateTime createdAt;
   final DateTime updatedAt;
   final DateTime? date; // Date prévue pour l'activité
+  final String? createdBy; // ID de l'utilisateur qui a créé l'activité
 
   Activity({
     required this.id,
@@ -42,6 +43,7 @@ class Activity {
     required this.createdAt,
     required this.updatedAt,
     this.date,
+    this.createdBy,
   });
 
   /// Calcule le score total des votes
@@ -108,6 +110,7 @@ class Activity {
     DateTime? updatedAt,
     DateTime? date,
     bool clearDate = false,
+    String? createdBy,
   }) {
     return Activity(
       id: id ?? this.id,
@@ -129,6 +132,7 @@ class Activity {
       createdAt: createdAt ?? this.createdAt,
       updatedAt: updatedAt ?? this.updatedAt,
       date: clearDate ? null : (date ?? this.date),
+      createdBy: createdBy ?? this.createdBy,
     );
   }
 
@@ -154,6 +158,7 @@ class Activity {
       'createdAt': Timestamp.fromDate(createdAt),
       'updatedAt': Timestamp.fromDate(updatedAt),
       'date': date != null ? Timestamp.fromDate(date!) : null,
+      'createdBy': createdBy,
     };
   }
 
@@ -179,6 +184,7 @@ class Activity {
       createdAt: (map['createdAt'] as Timestamp).toDate(),
       updatedAt: (map['updatedAt'] as Timestamp).toDate(),
       date: map['date'] != null ? (map['date'] as Timestamp).toDate() : null,
+      createdBy: map['createdBy'],
     );
   }
 
diff --git a/lib/services/notification_service.dart b/lib/services/notification_service.dart
index edf9096..87ef771 100644
--- a/lib/services/notification_service.dart
+++ b/lib/services/notification_service.dart
@@ -1,8 +1,16 @@
 import 'dart:io';
+import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter_local_notifications/flutter_local_notifications.dart';
+import 'package:firebase_core/firebase_core.dart';
 import 'package:travel_mate/services/logger_service.dart';
 
+@pragma('vm:entry-point')
+Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
+  await Firebase.initializeApp();
+  LoggerService.info('Handling a background message: ${message.messageId}');
+}
+
 class NotificationService {
   static final NotificationService _instance = NotificationService._internal();
   factory NotificationService() => _instance;
@@ -41,8 +49,24 @@ class NotificationService {
     // Handle foreground messages
     FirebaseMessaging.onMessage.listen(_handleForegroundMessage);
 
+    // Handle token refresh
+    FirebaseMessaging.instance.onTokenRefresh.listen(_onTokenRefresh);
+
     _isInitialized = true;
     LoggerService.info('NotificationService initialized');
+
+    // Print current token for debugging
+    final token = await getFCMToken();
+    LoggerService.info('Current FCM Token: $token');
+  }
+
+  Future<void> _onTokenRefresh(String newToken) async {
+    LoggerService.info('FCM Token refreshed: $newToken');
+    // We need the user ID to save the token.
+    // Since this service is a singleton, we might not have direct access to the user ID here
+    // without injecting the repository or bloc.
+    // For now, we rely on the AuthBloc to update the token on login/start.
+    // Ideally, we should save it here if we have the user ID.
   }
 
   Future<void> _requestPermissions() async {
@@ -85,6 +109,20 @@ class NotificationService {
     }
   }
 
+  Future<void> saveTokenToFirestore(String userId) async {
+    try {
+      final token = await getFCMToken();
+      if (token != null) {
+        await FirebaseFirestore.instance.collection('users').doc(userId).set({
+          'fcmToken': token,
+        }, SetOptions(merge: true));
+        LoggerService.info('FCM Token saved to Firestore for user: $userId');
+      }
+    } catch (e) {
+      LoggerService.error('Error saving FCM token to Firestore: $e');
+    }
+  }
+
   Future<void> _handleForegroundMessage(RemoteMessage message) async {
     LoggerService.info('Got a message whilst in the foreground!');
     LoggerService.info('Message data: ${message.data}');