sample json fix

lib/data/default_deck.dart

@@ -17,18 +17,21 @@ class DefaultDeck {
         prompt: 'What is the capital city of Australia?',
         answers: ['Sydney', 'Melbourne', 'Canberra', 'Perth'],
         correctAnswerIndices: [2],
+        explanation: 'Canberra was chosen as the capital in 1908 as a compromise between Sydney and Melbourne.',
       ),
       Question(
         id: 'gk_2',
         prompt: 'Which planet is known as the Red Planet?',
         answers: ['Venus', 'Mars', 'Jupiter', 'Saturn'],
         correctAnswerIndices: [1],
+        explanation: 'Mars appears red due to iron oxide (rust) on its surface.',
       ),
       Question(
         id: 'gk_3',
         prompt: 'What is the largest ocean on Earth?',
         answers: ['Atlantic Ocean', 'Indian Ocean', 'Arctic Ocean', 'Pacific Ocean'],
         correctAnswerIndices: [3],
+        explanation: 'The Pacific Ocean covers about 63 million square miles and is larger than all of Earth\'s land area combined.',
       ),
       Question(
         id: 'gk_4',
@@ -203,6 +206,7 @@ class DefaultDeck {
         prompt: 'What is the capital city of Australia?',
         answers: ['Sydney', 'Melbourne', 'Canberra', 'Perth'],
         correctAnswerIndices: [2],
+        explanation: 'Canberra was chosen as the capital in 1908 as a compromise between Sydney and Melbourne.',
         consecutiveCorrect: 3,
         isKnown: true,
         priorityPoints: 0,
@@ -216,6 +220,7 @@ class DefaultDeck {
         prompt: 'Which planet is known as the Red Planet?',
         answers: ['Venus', 'Mars', 'Jupiter', 'Saturn'],
         correctAnswerIndices: [1],
+        explanation: 'Mars appears red due to iron oxide (rust) on its surface.',
         consecutiveCorrect: 3,
         isKnown: true,
         priorityPoints: 0,
@@ -227,6 +232,7 @@ class DefaultDeck {
       Question(
         id: 'gk_3',
         prompt: 'What is the largest ocean on Earth?',
+        explanation: 'The Pacific Ocean covers about 63 million square miles and is larger than all of Earth\'s land area combined.',
         answers: ['Atlantic Ocean', 'Indian Ocean', 'Arctic Ocean', 'Pacific Ocean'],
         correctAnswerIndices: [3],
         consecutiveCorrect: 3,

lib/screens/attempt_result_screen.dart

@@ -3,6 +3,7 @@ import 'package:practice_engine/practice_engine.dart';
 import '../routes.dart';
 import '../widgets/status_chip.dart';
 import '../services/deck_storage.dart';
+import '../utils/top_snackbar.dart';
 
 class AttemptResultScreen extends StatefulWidget {
   const AttemptResultScreen({super.key});
@@ -14,6 +15,7 @@ class AttemptResultScreen extends StatefulWidget {
 class _AttemptResultScreenState extends State<AttemptResultScreen> {
   Deck? _deck;
   AttemptResult? _result;
+  Attempt? _completedAttempt;
   final DeckStorage _deckStorage = DeckStorage();
 
   @override
@@ -29,6 +31,7 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
       final args = ModalRoute.of(context)?.settings.arguments as Map<String, dynamic>?;
       _deck = args?['deck'] as Deck? ?? _createSampleDeck();
       _result = args?['result'] as AttemptResult? ?? _createSampleResult();
+      _completedAttempt = args?['attempt'] as Attempt?;
     }
   }
 
@@ -62,8 +65,17 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
 
   void _repeatSameAttempt() {
     if (_deck == null) return;
+    // Pass the completed attempt so the attempt screen uses the same questions in the same order
+    if (_completedAttempt != null && _completedAttempt!.questions.isNotEmpty) {
+      Navigator.pushReplacementNamed(
+        context,
+        Routes.attempt,
+        arguments: {'deck': _deck, 'repeatAttempt': _completedAttempt},
+      );
+    } else {
       Navigator.pushReplacementNamed(context, Routes.attempt, arguments: _deck);
     }
+  }
 
   void _newAttempt() {
     if (_deck == null) return;
@@ -74,11 +86,155 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
     if (_deck == null) return;
     // Save the updated deck to storage
     _deckStorage.saveDeckSync(_deck!);
-    // Navigate back to deck list
+    // Navigate back to this deck's overview (decks screen), not the home deck list
-    Navigator.pushNamedAndRemoveUntil(
+    Navigator.popUntil(context, (route) => route.settings.name == Routes.deckOverview);
+    Navigator.pushReplacementNamed(
       context,
-      Routes.deckList,
+      Routes.deckOverview,
-      (route) => false,
+      arguments: _deck,
+    );
+  }
+
+  Question? _currentQuestionInDeck(String questionId) {
+    if (_deck == null) return null;
+    try {
+      return _deck!.questions.firstWhere((q) => q.id == questionId);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  void _toggleFlag(String questionId) {
+    if (_deck == null) return;
+    setState(() {
+      _deck = DeckService.toggleQuestionFlag(deck: _deck!, questionId: questionId);
+    });
+    _deckStorage.saveDeckSync(_deck!);
+    final q = _currentQuestionInDeck(questionId);
+    showTopSnackBar(
+      context,
+      message: q?.isFlagged == true ? 'Question flagged for review' : 'Question unflagged',
+      backgroundColor: q?.isFlagged == true ? Colors.orange : null,
+    );
+  }
+
+  void _markNeedsPractice(String questionId) {
+    if (_deck == null) return;
+    setState(() {
+      _deck = DeckService.markQuestionAsNeedsPractice(deck: _deck!, questionId: questionId);
+    });
+    _deckStorage.saveDeckSync(_deck!);
+    showTopSnackBar(
+      context,
+      message: 'Marked as needs practice',
+      backgroundColor: Colors.blue,
+    );
+  }
+
+  void _showQuestionDetail(AnswerResult answerResult) {
+    final q = answerResult.question;
+    final correctSet = q.correctIndices.toSet();
+    final userSet = answerResult.userAnswerIndices.toSet();
+    showDialog<void>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Question'),
+        content: SingleChildScrollView(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              Text(
+                q.prompt,
+                style: Theme.of(context).textTheme.titleMedium,
+              ),
+              const SizedBox(height: 16),
+              ...q.answers.asMap().entries.map((e) {
+                final i = e.key;
+                final answer = e.value;
+                final isCorrect = correctSet.contains(i);
+                final isUser = userSet.contains(i);
+                String? label;
+                Color? color;
+                if (isCorrect && isUser) {
+                  label = 'Correct (your answer)';
+                  color = Colors.green;
+                } else if (isCorrect) {
+                  label = 'Correct';
+                  color = Colors.green;
+                } else if (isUser) {
+                  label = 'Your answer';
+                  color = Colors.red;
+                }
+                return Padding(
+                  padding: const EdgeInsets.only(bottom: 8),
+                  child: Row(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      SizedBox(
+                        width: 24,
+                        child: isCorrect
+                            ? Icon(Icons.check_circle, color: Colors.green, size: 20)
+                            : isUser
+                                ? Icon(Icons.cancel, color: Colors.red, size: 20)
+                                : const Icon(Icons.radio_button_unchecked, size: 20, color: Colors.grey),
+                      ),
+                      const SizedBox(width: 8),
+                      Expanded(
+                        child: Text.rich(
+                          TextSpan(
+                            children: [
+                              if (label != null)
+                                TextSpan(
+                                  text: '$label: ',
+                                  style: TextStyle(
+                                    color: color,
+                                    fontWeight: FontWeight.bold,
+                                    fontSize: Theme.of(context).textTheme.bodyLarge?.fontSize,
+                                  ),
+                                ),
+                              TextSpan(
+                                text: answer,
+                                style: TextStyle(
+                                  color: color,
+                                  fontWeight: label != null ? FontWeight.bold : null,
+                                  fontSize: Theme.of(context).textTheme.bodyLarge?.fontSize,
+                                ),
+                              ),
+                            ],
+                          ),
+                        ),
+                      ),
+                    ],
+                  ),
+                );
+              }),
+              if (q.explanation != null && q.explanation!.trim().isNotEmpty) ...[
+                const SizedBox(height: 16),
+                const Divider(),
+                const SizedBox(height: 8),
+                Text(
+                  'Explanation',
+                  style: Theme.of(context).textTheme.titleSmall?.copyWith(
+                    fontWeight: FontWeight.bold,
+                  ),
+                ),
+                const SizedBox(height: 4),
+                Text(
+                  q.explanation!,
+                  style: Theme.of(context).textTheme.bodyMedium,
+                ),
+              ],
+            ],
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: const Text('Close'),
+          ),
+        ],
+      ),
     );
   }
 
@@ -217,6 +373,8 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
               ),
               const SizedBox(height: 12),
               ..._result!.incorrectQuestions.map((answerResult) {
+                final currentQ = _currentQuestionInDeck(answerResult.question.id);
+                final isFlagged = currentQ?.isFlagged ?? false;
                 return Card(
                   margin: const EdgeInsets.only(bottom: 8),
                   child: Padding(
@@ -227,28 +385,63 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
                         Text(
                           answerResult.question.prompt,
                           style: Theme.of(context).textTheme.titleMedium,
+                          overflow: TextOverflow.ellipsis,
+                          maxLines: 3,
                         ),
-                        const SizedBox(height: 12),
+                        const SizedBox(height: 8),
-                        Row(
-                          children: [
-                            StatusChip(statusChange: answerResult.statusChange),
-                            const Spacer(),
                         Text(
-                          'Your answer${answerResult.userAnswerIndices.length > 1 ? 's' : ''}: ${answerResult.userAnswerIndices.map((idx) => answerResult.question.answers[idx]).join(', ')}',
+                          answerResult.userAnswerIndices.isEmpty
+                              ? 'No answer'
+                              : 'Your answer${answerResult.userAnswerIndices.length > 1 ? 's' : ''}: ${answerResult.userAnswerIndices.map((idx) => answerResult.question.answers[idx]).join(', ')}',
                           style: TextStyle(
                             color: Colors.red,
                             fontWeight: FontWeight.bold,
+                            fontSize: Theme.of(context).textTheme.bodyMedium?.fontSize,
                           ),
+                          overflow: TextOverflow.ellipsis,
+                          maxLines: 2,
                         ),
-                      ],
+                        const SizedBox(height: 4),
-                    ),
-                    const SizedBox(height: 8),
                         Text(
                           'Correct answer${answerResult.question.correctIndices.length > 1 ? 's' : ''}: ${answerResult.question.correctIndices.map((idx) => answerResult.question.answers[idx]).join(', ')}',
                           style: TextStyle(
                             color: Colors.green,
                             fontWeight: FontWeight.bold,
+                            fontSize: Theme.of(context).textTheme.bodyMedium?.fontSize,
                           ),
+                          overflow: TextOverflow.ellipsis,
+                          maxLines: 2,
+                        ),
+                        const SizedBox(height: 12),
+                        Row(
+                          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                          children: [
+                            StatusChip(statusChange: answerResult.statusChange),
+                            Row(
+                              mainAxisSize: MainAxisSize.min,
+                              children: [
+                                IconButton(
+                                  onPressed: () => _showQuestionDetail(answerResult),
+                                  icon: const Icon(Icons.visibility, size: 22),
+                                  tooltip: 'View question details',
+                                ),
+                                IconButton(
+                                  onPressed: () => _markNeedsPractice(answerResult.question.id),
+                                  icon: const Icon(Icons.replay, size: 22),
+                                  tooltip: 'Mark as needs practice',
+                                ),
+                                IconButton(
+                                  onPressed: () => _toggleFlag(answerResult.question.id),
+                                  icon: Icon(
+                                    isFlagged ? Icons.flag : Icons.outlined_flag,
+                                    color: isFlagged ? Colors.red : null,
+                                    size: 22,
+                                  ),
+                                  tooltip: isFlagged ? 'Unflag' : 'Flag for review',
+                                ),
+                              ],
+                            ),
+                          ],
                         ),
                       ],
                     ),
@@ -265,16 +458,65 @@ class _AttemptResultScreenState extends State<AttemptResultScreen> {
             ),
             const SizedBox(height: 12),
             ..._result!.allResults.map((answerResult) {
+              final currentQ = _currentQuestionInDeck(answerResult.question.id);
+              final isFlagged = currentQ?.isFlagged ?? false;
               return Card(
                 margin: const EdgeInsets.only(bottom: 8),
-                child: ListTile(
+                child: Padding(
-                  title: Text(answerResult.question.prompt),
+                  padding: const EdgeInsets.all(16),
-                  subtitle: Text(
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      Text(
+                        answerResult.question.prompt,
+                        style: Theme.of(context).textTheme.titleMedium,
+                        overflow: TextOverflow.ellipsis,
+                        maxLines: 3,
+                      ),
+                      const SizedBox(height: 4),
+                      Text(
                         answerResult.isCorrect
                             ? 'Correct'
+                            : answerResult.userAnswerIndices.isEmpty
+                                ? 'Incorrect - No answer'
                                 : 'Incorrect - Selected: ${answerResult.userAnswerIndices.map((idx) => answerResult.question.answers[idx]).join(', ')}',
+                        style: Theme.of(context).textTheme.bodyMedium,
+                        overflow: TextOverflow.ellipsis,
+                        maxLines: 2,
+                      ),
+                      const SizedBox(height: 12),
+                      Row(
+                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                        children: [
+                          StatusChip(statusChange: answerResult.statusChange),
+                          Row(
+                            mainAxisSize: MainAxisSize.min,
+                            children: [
+                              IconButton(
+                                onPressed: () => _showQuestionDetail(answerResult),
+                                icon: const Icon(Icons.visibility, size: 22),
+                                tooltip: 'View question details',
+                              ),
+                              IconButton(
+                                onPressed: () => _markNeedsPractice(answerResult.question.id),
+                                icon: const Icon(Icons.replay, size: 22),
+                                tooltip: 'Mark as needs practice',
+                              ),
+                              IconButton(
+                                onPressed: () => _toggleFlag(answerResult.question.id),
+                                icon: Icon(
+                                  isFlagged ? Icons.flag : Icons.outlined_flag,
+                                  color: isFlagged ? Colors.red : null,
+                                  size: 22,
+                                ),
+                                tooltip: isFlagged ? 'Unflag' : 'Flag for review',
+                              ),
+                            ],
+                          ),
+                        ],
+                      ),
+                    ],
                   ),
-                  trailing: StatusChip(statusChange: answerResult.statusChange),
                 ),
               );
             }),

lib/screens/attempt_screen.dart

@@ -101,6 +101,8 @@ class _AttemptScreenState extends State<AttemptScreen> {
       bool? includeKnown;
       bool? resumeAttempt;
       
+      final repeatAttempt = args is Map<String, dynamic> ? args['repeatAttempt'] as Attempt? : null;
+
       if (args is Map<String, dynamic>) {
         _deck = args['deck'] as Deck? ?? _createSampleDeck();
         includeKnown = args['includeKnown'] as bool?;
@@ -113,8 +115,35 @@ class _AttemptScreenState extends State<AttemptScreen> {
         resumeAttempt = false;
       }
 
-      // Check if we should resume an incomplete attempt
+      // Check if we should repeat the exact same attempt (same questions, same order)
-      if (resumeAttempt == true && _deck!.incompleteAttempt != null) {
+      if (repeatAttempt != null && repeatAttempt.questions.isNotEmpty) {
+        final orderedIds = repeatAttempt.questions.map((q) => q.id).toList();
+        final questions = <Question>[];
+        for (final id in orderedIds) {
+          final q = _deck!.questions.where((q) => q.id == id).firstOrNull;
+          if (q != null) questions.add(q);
+        }
+        if (questions.isNotEmpty) {
+          _attempt = Attempt(
+            id: 'repeat-${DateTime.now().millisecondsSinceEpoch}',
+            questions: questions,
+            startTime: DateTime.now().millisecondsSinceEpoch,
+          );
+          // Same as new attempt: randomize answer order per question when config enables it
+          _answerOrderPerQuestion = {};
+          final shuffleAnswers = _deck!.config.shuffleAnswerOrder;
+          for (final q in _attempt!.questions) {
+            final order = List.generate(q.answers.length, (i) => i);
+            if (shuffleAnswers) {
+              order.shuffle(math.Random());
+            }
+            _answerOrderPerQuestion[q.id] = order;
+          }
+        }
+      }
+
+      // If not repeating, check if we should resume an incomplete attempt
+      if (_attempt == null && resumeAttempt == true && _deck!.incompleteAttempt != null) {
         final incomplete = _deck!.incompleteAttempt!;
         _attempt = incomplete.toAttempt(_deck!.questions);
         _currentQuestionIndex = incomplete.currentQuestionIndex;
@@ -133,7 +162,10 @@ class _AttemptScreenState extends State<AttemptScreen> {
             _pageController.jumpToPage(_currentQuestionIndex);
           }
         });
-      } else {
+      }
+
+      // Otherwise create a new attempt
+      if (_attempt == null) {
         _attempt = _attemptService!.createAttempt(
           deck: _deck!,
           includeKnown: includeKnown,

lib/screens/deck_config_screen.dart

@@ -1,4 +1,7 @@
+import 'dart:convert';
+
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import '../utils/top_snackbar.dart';
 import 'package:practice_engine/practice_engine.dart';
 import '../services/deck_storage.dart';
@@ -135,8 +138,10 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
     super.dispose();
   }
 
-  void _save() {
+  /// Builds config from current form state, validates, persists if valid.
-    if (_deck == null || _config == null) return;
+  /// Returns true if saved, false if validation failed.
+  bool _applyAndPersist() {
+    if (_deck == null || _config == null) return false;
 
     final consecutive = int.tryParse(_consecutiveController.text);
     final attemptSize = int.tryParse(_attemptSizeController.text);
@@ -153,7 +158,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
           backgroundColor: Colors.red,
         ),
       );
-      return;
+      return false;
     }
 
     if (consecutive < 1 ||
@@ -166,7 +171,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
           backgroundColor: Colors.red,
         ),
       );
-      return;
+      return false;
     }
 
     // Calculate time limit in seconds
@@ -186,7 +191,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
             backgroundColor: Colors.red,
           ),
         );
-        return;
+        return false;
       }
     }
 
@@ -203,21 +208,78 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
     );
 
     final updatedDeck = _deck!.copyWith(config: updatedConfig);
+    final deckStorage = DeckStorage();
+    deckStorage.saveDeckSync(updatedDeck);
 
-    // Show success message
+    setState(() {
+      _deck = updatedDeck;
+      _config = updatedConfig;
+      _configHashCode = updatedConfig.hashCode;
+    });
+    return true;
+  }
+
+  Map<String, dynamic> _configToJsonMap() {
+    int? timeLimitSeconds;
+    if (_timeLimitEnabled) {
+      final hours = int.tryParse(_timeLimitHoursController.text) ?? 0;
+      final minutes = int.tryParse(_timeLimitMinutesController.text) ?? 0;
+      final seconds = int.tryParse(_timeLimitSecondsController.text) ?? 0;
+      timeLimitSeconds = hours * 3600 + minutes * 60 + seconds;
+      if (timeLimitSeconds == 0) timeLimitSeconds = null;
+    }
+    return {
+      'requiredConsecutiveCorrect': int.tryParse(_consecutiveController.text) ?? _config!.requiredConsecutiveCorrect,
+      'defaultAttemptSize': int.tryParse(_attemptSizeController.text) ?? _config!.defaultAttemptSize,
+      'priorityIncreaseOnIncorrect': int.tryParse(_priorityIncreaseController.text) ?? _config!.priorityIncreaseOnIncorrect,
+      'priorityDecreaseOnCorrect': int.tryParse(_priorityDecreaseController.text) ?? _config!.priorityDecreaseOnCorrect,
+      'immediateFeedbackEnabled': _immediateFeedback,
+      'includeKnownInAttempts': _includeKnownInAttempts,
+      'shuffleAnswerOrder': _shuffleAnswerOrder,
+      'excludeFlaggedQuestions': _excludeFlaggedQuestions,
+      if (timeLimitSeconds != null) 'timeLimitSeconds': timeLimitSeconds,
+    };
+  }
+
+  void _showAsJson() {
+    if (_deck == null || _config == null) return;
+    final map = _configToJsonMap();
+    final jsonString = const JsonEncoder.withIndent('  ').convert(map);
+    showDialog<void>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Attempt Settings as JSON'),
+        content: SingleChildScrollView(
+          child: SelectableText(
+            jsonString,
+            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+              fontFamily: 'monospace',
+              fontSize: 12,
+            ),
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: const Text('Close'),
+          ),
+          FilledButton.icon(
+            onPressed: () {
+              Clipboard.setData(ClipboardData(text: jsonString));
+              Navigator.pop(context);
               showTopSnackBar(
                 context,
-      message: 'Deck configuration saved successfully',
+                message: 'JSON copied to clipboard',
                 backgroundColor: Colors.green,
                 duration: const Duration(seconds: 1),
               );
-
+            },
-    // Pop with the updated deck
+            icon: const Icon(Icons.copy, size: 20),
-    Navigator.pop(context, updatedDeck);
+            label: const Text('Copy'),
-  }
+          ),
-
+        ],
-  void _cancel() {
+      ),
-    Navigator.pop(context);
+    );
   }
 
   void _editDeck() {
@@ -307,7 +369,18 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
 
     return Scaffold(
       appBar: AppBar(
-        title: const Text('Deck Configuration'),
+        title: const Text('Attempt Settings'),
+        leading: IconButton(
+          icon: const Icon(Icons.arrow_back),
+          onPressed: () => Navigator.pop(context, _deck),
+        ),
+        actions: [
+          IconButton(
+            icon: const Icon(Icons.code),
+            onPressed: _showAsJson,
+            tooltip: 'Show as JSON',
+          ),
+        ],
       ),
       body: SingleChildScrollView(
         padding: const EdgeInsets.all(16),
@@ -335,6 +408,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         border: OutlineInputBorder(),
                       ),
                       keyboardType: TextInputType.number,
+                      onEditingComplete: _applyAndPersist,
                     ),
                     const SizedBox(height: 16),
 
@@ -347,6 +421,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         border: OutlineInputBorder(),
                       ),
                       keyboardType: TextInputType.number,
+                      onEditingComplete: _applyAndPersist,
                     ),
                     const SizedBox(height: 16),
 
@@ -359,6 +434,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         border: OutlineInputBorder(),
                       ),
                       keyboardType: TextInputType.number,
+                      onEditingComplete: _applyAndPersist,
                     ),
                     const SizedBox(height: 16),
 
@@ -371,6 +447,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         border: OutlineInputBorder(),
                       ),
                       keyboardType: TextInputType.number,
+                      onEditingComplete: _applyAndPersist,
                     ),
                     const SizedBox(height: 16),
 
@@ -385,6 +462,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         setState(() {
                           _immediateFeedback = value;
                         });
+                        _applyAndPersist();
                       },
                     ),
                     const SizedBox(height: 16),
@@ -400,6 +478,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         setState(() {
                           _includeKnownInAttempts = value;
                         });
+                        _applyAndPersist();
                       },
                     ),
                     const SizedBox(height: 16),
@@ -415,6 +494,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         setState(() {
                           _shuffleAnswerOrder = value;
                         });
+                        _applyAndPersist();
                       },
                     ),
                     const SizedBox(height: 16),
@@ -430,6 +510,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                         setState(() {
                           _excludeFlaggedQuestions = value;
                         });
+                        _applyAndPersist();
                       },
                     ),
                     const SizedBox(height: 16),
@@ -450,6 +531,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                             _timeLimitSecondsController.clear();
                           }
                         });
+                        _applyAndPersist();
                       },
                     ),
                     if (_timeLimitEnabled) ...[
@@ -464,6 +546,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                                 border: OutlineInputBorder(),
                               ),
                               keyboardType: TextInputType.number,
+                              onEditingComplete: _applyAndPersist,
                             ),
                           ),
                           const SizedBox(width: 8),
@@ -475,6 +558,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                                 border: OutlineInputBorder(),
                               ),
                               keyboardType: TextInputType.number,
+                              onEditingComplete: _applyAndPersist,
                             ),
                           ),
                           const SizedBox(width: 8),
@@ -486,6 +570,7 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                                 border: OutlineInputBorder(),
                               ),
                               keyboardType: TextInputType.number,
+                              onEditingComplete: _applyAndPersist,
                             ),
                           ),
                         ],
@@ -579,26 +664,6 @@ class _DeckConfigScreenState extends State<DeckConfigScreen> {
                 ),
               ),
             ),
-            const SizedBox(height: 24),
-
-            // Action Buttons
-            Row(
-              children: [
-                Expanded(
-                  child: OutlinedButton(
-                    onPressed: _cancel,
-                    child: const Text('Cancel'),
-                  ),
-                ),
-                const SizedBox(width: 16),
-                Expanded(
-                  child: FilledButton(
-                    onPressed: _save,
-                    child: const Text('Save'),
-                  ),
-                ),
-              ],
-            ),
           ],
         ),
       ),

lib/screens/deck_edit_screen.dart

@@ -1,4 +1,7 @@
+import 'dart:convert';
+
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import '../utils/top_snackbar.dart';
 import 'package:practice_engine/practice_engine.dart';
 import '../services/deck_storage.dart';
@@ -16,6 +19,8 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
   late TextEditingController _descriptionController;
   final List<QuestionEditor> _questionEditors = [];
   final DeckStorage _deckStorage = DeckStorage();
+  final ScrollController _scrollController = ScrollController();
+  int? _focusNewQuestionIndex;
 
   @override
   void initState() {
@@ -48,6 +53,7 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
 
   @override
   void dispose() {
+    _scrollController.dispose();
     _titleController.dispose();
     _descriptionController.dispose();
     for (final editor in _questionEditors) {
@@ -59,6 +65,21 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
   void _addQuestion() {
     setState(() {
       _questionEditors.add(QuestionEditor.empty());
+      _focusNewQuestionIndex = _questionEditors.length - 1;
+    });
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      final pos = _scrollController.position;
+      if (pos.maxScrollExtent > pos.pixels) {
+        _scrollController.animateTo(
+          pos.maxScrollExtent,
+          duration: const Duration(milliseconds: 300),
+          curve: Curves.easeOut,
+        );
+      }
+      Future.microtask(() {
+        if (mounted) setState(() => _focusNewQuestionIndex = null);
+      });
     });
   }
 
@@ -131,6 +152,28 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
     Navigator.pop(context, updatedDeck);
   }
 
+  void _copyQuestionsJson() {
+    if (_questionEditors.isEmpty) {
+      showTopSnackBar(context, message: 'No questions to copy');
+      return;
+    }
+    final questions = _questionEditors.map((e) => e.toQuestion()).toList();
+    final list = questions.map((q) => {
+      'id': q.id,
+      'prompt': q.prompt,
+      if (q.explanation != null && q.explanation!.isNotEmpty) 'explanation': q.explanation,
+      'answers': q.answers,
+      'correctAnswerIndices': q.correctAnswerIndices,
+    }).toList();
+    final jsonString = const JsonEncoder.withIndent('  ').convert(list);
+    Clipboard.setData(ClipboardData(text: jsonString));
+    showTopSnackBar(
+      context,
+      message: '${questions.length} question(s) copied as JSON',
+      backgroundColor: Colors.green,
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     if (_deck == null) {
@@ -143,6 +186,11 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
       appBar: AppBar(
         title: const Text('Edit Deck'),
         actions: [
+          IconButton(
+            icon: const Icon(Icons.copy),
+            onPressed: _copyQuestionsJson,
+            tooltip: 'Copy questions as JSON',
+          ),
           IconButton(
             icon: const Icon(Icons.add),
             onPressed: _addQuestion,
@@ -156,6 +204,7 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
         ],
       ),
       body: SingleChildScrollView(
+        controller: _scrollController,
         padding: const EdgeInsets.all(16),
         child: Column(
           crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -197,6 +246,7 @@ class _DeckEditScreenState extends State<DeckEditScreen> {
                 onDelete: () => _removeQuestion(index),
                 onUnflag: null,
                 onChanged: () => setState(() {}),
+                requestFocusOnPrompt: _focusNewQuestionIndex == index,
               );
             }),
 
@@ -243,6 +293,7 @@ class QuestionEditorCard extends StatefulWidget {
   final VoidCallback? onDelete;
   final VoidCallback? onUnflag;
   final VoidCallback onChanged;
+  final bool requestFocusOnPrompt;
 
   const QuestionEditorCard({
     super.key,
@@ -251,6 +302,7 @@ class QuestionEditorCard extends StatefulWidget {
     this.onDelete,
     this.onUnflag,
     required this.onChanged,
+    this.requestFocusOnPrompt = false,
   });
 
   @override
@@ -258,8 +310,31 @@ class QuestionEditorCard extends StatefulWidget {
 }
 
 class _QuestionEditorCardState extends State<QuestionEditorCard> {
+  final FocusNode _promptFocusNode = FocusNode();
+
+  @override
+  void dispose() {
+    _promptFocusNode.dispose();
+    super.dispose();
+  }
+
+  @override
+  void didUpdateWidget(QuestionEditorCard oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.requestFocusOnPrompt && !oldWidget.requestFocusOnPrompt) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) _promptFocusNode.requestFocus();
+      });
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
+    if (widget.requestFocusOnPrompt) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) _promptFocusNode.requestFocus();
+      });
+    }
     return Card(
       margin: const EdgeInsets.only(bottom: 16),
       child: Padding(
@@ -297,12 +372,23 @@ class _QuestionEditorCardState extends State<QuestionEditorCard> {
             // Question Prompt
             TextField(
               controller: widget.editor.promptController,
+              focusNode: _promptFocusNode,
               decoration: const InputDecoration(
                 labelText: 'Question',
                 border: OutlineInputBorder(),
               ),
               maxLines: 2,
             ),
+            const SizedBox(height: 12),
+            TextField(
+              controller: widget.editor.explanationController,
+              decoration: const InputDecoration(
+                labelText: 'Explanation (optional)',
+                helperText: 'Shown when viewing question details after an attempt',
+                border: OutlineInputBorder(),
+              ),
+              maxLines: 3,
+            ),
             const SizedBox(height: 16),
 
             // Answers
@@ -399,12 +485,14 @@ class _QuestionEditorCardState extends State<QuestionEditorCard> {
 
 class QuestionEditor {
   final TextEditingController promptController;
+  final TextEditingController explanationController;
   final List<TextEditingController> answerControllers;
   Set<int> correctAnswerIndices;
   final String? originalId;
 
   QuestionEditor({
     required this.promptController,
+    required this.explanationController,
     required this.answerControllers,
     Set<int>? correctAnswerIndices,
     this.originalId,
@@ -413,6 +501,7 @@ class QuestionEditor {
   factory QuestionEditor.fromQuestion(Question question) {
     return QuestionEditor(
       promptController: TextEditingController(text: question.prompt),
+      explanationController: TextEditingController(text: question.explanation ?? ''),
       answerControllers: question.answers
           .map((answer) => TextEditingController(text: answer))
           .toList(),
@@ -424,6 +513,7 @@ class QuestionEditor {
   factory QuestionEditor.empty() {
     return QuestionEditor(
       promptController: TextEditingController(),
+      explanationController: TextEditingController(),
       answerControllers: [
         TextEditingController(),
         TextEditingController(),
@@ -446,9 +536,11 @@ class QuestionEditor {
   }
 
   Question toQuestion() {
+    final explanationText = explanationController.text.trim();
     return Question(
       id: originalId ?? DateTime.now().millisecondsSinceEpoch.toString(),
       prompt: promptController.text.trim(),
+      explanation: explanationText.isEmpty ? null : explanationText,
       answers: answerControllers.map((c) => c.text.trim()).toList(),
       correctAnswerIndices: correctAnswerIndices.toList()..sort(),
     );
@@ -456,6 +548,7 @@ class QuestionEditor {
 
   void dispose() {
     promptController.dispose();
+    explanationController.dispose();
     for (final controller in answerControllers) {
       controller.dispose();
     }

lib/screens/deck_import_screen.dart

@@ -64,6 +64,7 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
         return Question(
           id: questionMap['id'] as String? ?? '',
           prompt: questionMap['prompt'] as String? ?? '',
+          explanation: questionMap['explanation'] as String?,
           answers: (questionMap['answers'] as List<dynamic>?)
                   ?.map((e) => e.toString())
                   .toList() ??
@@ -118,7 +119,96 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
       final deckStorage = DeckStorage();
       deckStorage.saveDeckSync(deck);
 
-      // Navigate back to deck list
+      showTopSnackBar(
+        context,
+        message: 'Deck created successfully',
+        backgroundColor: Colors.green,
+      );
+      Navigator.pop(context);
+    } catch (e) {
+      setState(() {
+        _errorMessage = e.toString();
+        _isLoading = false;
+      });
+    }
+  }
+
+  void _mergeWithExistingDeck() async {
+    setState(() {
+      _errorMessage = null;
+      _isLoading = true;
+    });
+
+    try {
+      if (_jsonController.text.trim().isEmpty) {
+        throw FormatException('Please enter JSON data');
+      }
+
+      final parsedDeck = _parseDeckFromJson(_jsonController.text.trim());
+      if (parsedDeck == null || parsedDeck.questions.isEmpty) {
+        throw FormatException(
+          parsedDeck == null
+              ? 'Failed to parse deck'
+              : 'JSON deck must contain at least one question to merge',
+        );
+      }
+      final deckToMerge = parsedDeck;
+
+      final deckStorage = DeckStorage();
+      final existingDecks = deckStorage.getAllDecksSync();
+      if (existingDecks.isEmpty) {
+        throw FormatException('No existing decks to merge into. Create or import a deck first.');
+      }
+
+      setState(() => _isLoading = false);
+
+      final selectedDeck = await showDialog<Deck>(
+        context: context,
+        builder: (context) => AlertDialog(
+          title: const Text('Merge with existing deck'),
+          content: SizedBox(
+            width: double.maxFinite,
+            child: ListView.builder(
+              shrinkWrap: true,
+              itemCount: existingDecks.length,
+              itemBuilder: (context, index) {
+                final deck = existingDecks[index];
+                return ListTile(
+                  title: Text(deck.title),
+                  subtitle: Text('${deck.questions.length} questions'),
+                  onTap: () => Navigator.pop(context, deck),
+                );
+              },
+            ),
+          ),
+          actions: [
+            TextButton(
+              onPressed: () => Navigator.pop(context),
+              child: const Text('Cancel'),
+            ),
+          ],
+        ),
+      );
+
+      if (selectedDeck == null || !mounted) return;
+
+      final timestamp = DateTime.now().millisecondsSinceEpoch;
+      final mergedQuestions = [
+        ...selectedDeck.questions,
+        ...deckToMerge.questions.asMap().entries.map((e) {
+          final q = e.value;
+          final i = e.key;
+          return q.copyWith(id: '${q.id}_merged_${timestamp}_$i');
+        }),
+      ];
+      final mergedDeck = selectedDeck.copyWith(questions: mergedQuestions);
+      deckStorage.saveDeckSync(mergedDeck);
+
+      showTopSnackBar(
+        context,
+        message: 'Added ${deckToMerge.questions.length} question(s) to "${selectedDeck.title}"',
+        backgroundColor: Colors.green,
+      );
       Navigator.pop(context);
     } catch (e) {
       setState(() {
@@ -258,6 +348,7 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
           'prompt': 'Sample Question $i?',
           'answers': ['Answer A', 'Answer B', 'Answer C', 'Answer D'],
           'correctAnswerIndices': [i % 4],
+          if (i == 0) 'explanation': 'Optional explanation shown when viewing question details after an attempt.',
           'isKnown': i < 5,
         };
       }),
@@ -391,12 +482,12 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
                     Text(
-                      'Import Deck from JSON',
+                      'Import from JSON',
                       style: Theme.of(context).textTheme.titleLarge,
                     ),
                     const SizedBox(height: 8),
                     Text(
-                      'Paste your deck JSON below. The format should include id, title, description, config, and questions.',
+                      'Paste your deck JSON below. Create a new deck or merge questions into an existing one.',
                       style: Theme.of(context).textTheme.bodyMedium,
                     ),
                   ],
@@ -412,24 +503,18 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
                 child: Column(
                   crossAxisAlignment: CrossAxisAlignment.stretch,
                   children: [
-                    Row(
+                    Wrap(
-                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                      spacing: 8,
-                      children: [
+                      runSpacing: 4,
-                        Text(
-                          'Deck JSON',
-                          style: Theme.of(context).textTheme.titleMedium,
-                        ),
-                        Row(
-                          mainAxisSize: MainAxisSize.min,
                       children: [
                         TextButton.icon(
                           onPressed: _pickJsonFile,
-                              icon: const Icon(Icons.folder_open),
+                          icon: const Icon(Icons.folder_open, size: 20),
                           label: const Text('Select file'),
                         ),
                         TextButton.icon(
                           onPressed: _loadSampleDeck,
-                              icon: const Icon(Icons.description),
+                          icon: const Icon(Icons.description, size: 20),
                           label: const Text('Load Sample'),
                         ),
                         IconButton(
@@ -439,8 +524,6 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
                         ),
                       ],
                     ),
-                      ],
-                    ),
                     const SizedBox(height: 8),
                     TextField(
                       controller: _jsonController,
@@ -484,8 +567,28 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
 
             if (_errorMessage != null) const SizedBox(height: 16),
 
-            // Import Button
+            // Import and Merge Buttons
-            FilledButton.icon(
+            Row(
+              children: [
+                Expanded(
+                  child: OutlinedButton.icon(
+                    onPressed: _isLoading ? null : _mergeWithExistingDeck,
+                    icon: _isLoading
+                        ? const SizedBox(
+                            width: 20,
+                            height: 20,
+                            child: CircularProgressIndicator(strokeWidth: 2),
+                          )
+                        : const Icon(Icons.merge_type, size: 20),
+                    label: Text(_isLoading ? '...' : 'Merge with deck'),
+                    style: OutlinedButton.styleFrom(
+                      padding: const EdgeInsets.symmetric(vertical: 16),
+                    ),
+                  ),
+                ),
+                const SizedBox(width: 12),
+                Expanded(
+                  child: FilledButton.icon(
                     onPressed: _isLoading ? null : _importDeck,
                     icon: _isLoading
                         ? const SizedBox(
@@ -493,12 +596,15 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
                             height: 20,
                             child: CircularProgressIndicator(strokeWidth: 2),
                           )
-                  : const Icon(Icons.upload),
+                        : const Icon(Icons.add_circle_outline, size: 20),
-              label: Text(_isLoading ? 'Importing...' : 'Import Deck'),
+                    label: Text(_isLoading ? 'Importing...' : 'Import and create deck'),
                     style: FilledButton.styleFrom(
                       padding: const EdgeInsets.symmetric(vertical: 16),
                     ),
                   ),
+                ),
+              ],
+            ),
 
             const SizedBox(height: 16),
 
@@ -531,6 +637,7 @@ class _DeckImportScreenState extends State<DeckImportScreen> {
                       const Text('• answers: array of strings (required)'),
                       const Text('• correctAnswerIndex: number (deprecated, use correctAnswerIndices)'),
                       const Text('• correctAnswerIndices: array of numbers (for multiple correct answers)'),
+                      const Text('• explanation: string (optional, shown when viewing question details)'),
                       const Text('• isKnown: boolean (optional)'),
                       const Text('• consecutiveCorrect: number (optional)'),
                       const Text('• priorityPoints: number (optional)'),

lib/screens/deck_list_screen.dart

@@ -102,6 +102,68 @@ class _DeckListScreenState extends State<DeckListScreen> {
     });
   }
 
+  void _mergeDeck(Deck sourceDeck) async {
+    final otherDecks = _decks.where((d) => d.id != sourceDeck.id).toList();
+    if (otherDecks.isEmpty) {
+      showTopSnackBar(
+        context,
+        message: 'No other deck to merge with',
+        backgroundColor: Colors.orange,
+      );
+      return;
+    }
+
+    final targetDeck = await showDialog<Deck>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Merge with deck'),
+        content: SizedBox(
+          width: double.maxFinite,
+          child: ListView.builder(
+            shrinkWrap: true,
+            itemCount: otherDecks.length,
+            itemBuilder: (context, index) {
+              final deck = otherDecks[index];
+              return ListTile(
+                title: Text(deck.title),
+                subtitle: Text('${deck.questions.length} questions'),
+                onTap: () => Navigator.pop(context, deck),
+              );
+            },
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: const Text('Cancel'),
+          ),
+        ],
+      ),
+    );
+
+    if (targetDeck == null || !mounted) return;
+
+    final timestamp = DateTime.now().millisecondsSinceEpoch;
+    final mergedQuestions = [
+      ...targetDeck.questions,
+      ...sourceDeck.questions.asMap().entries.map((e) {
+        final q = e.value;
+        final i = e.key;
+        return q.copyWith(id: '${q.id}_merged_${timestamp}_$i');
+      }),
+    ];
+    final mergedDeck = targetDeck.copyWith(questions: mergedQuestions);
+    _deckStorage.saveDeckSync(mergedDeck);
+    _loadDecks();
+    if (mounted) {
+      showTopSnackBar(
+        context,
+        message: 'Merged ${sourceDeck.questions.length} question(s) into "${targetDeck.title}"',
+        backgroundColor: Colors.green,
+      );
+    }
+  }
+
   void _cloneDeck(Deck deck) {
     // Create a copy of the deck with a new ID and reset progress
     final clonedDeck = deck.copyWith(
@@ -452,6 +514,21 @@ class _DeckListScreenState extends State<DeckListScreen> {
                                         );
                                       },
                                     ),
+                                    PopupMenuItem(
+                                      child: const Row(
+                                        children: [
+                                          Icon(Icons.merge_type, color: Colors.teal),
+                                          SizedBox(width: 8),
+                                          Text('Merge'),
+                                        ],
+                                      ),
+                                      onTap: () {
+                                        Future.delayed(
+                                          const Duration(milliseconds: 100),
+                                          () => _mergeDeck(deck),
+                                        );
+                                      },
+                                    ),
                                     PopupMenuItem(
                                       child: const Row(
                                         children: [

lib/screens/flagged_questions_screen.dart

@@ -73,6 +73,68 @@ class _FlaggedQuestionsScreenState extends State<FlaggedQuestionsScreen> {
     showTopSnackBar(context, message: 'Question unflagged');
   }
 
+  void _removeQuestion(int index) {
+    if (_deck == null || index < 0 || index >= _editors.length) return;
+    final questionId = _editors[index].originalId;
+    if (questionId == null) return;
+    final updatedQuestions =
+        _deck!.questions.where((q) => q.id != questionId).toList();
+    final updatedDeck = _deck!.copyWith(questions: updatedQuestions);
+    _deckStorage.saveDeckSync(updatedDeck);
+    _editors[index].dispose();
+    setState(() {
+      _deck = updatedDeck;
+      _editors.removeAt(index);
+    });
+    showTopSnackBar(context, message: 'Question removed from deck');
+  }
+
+  Future<void> _removeAllQuestions() async {
+    if (_deck == null || _editors.isEmpty) return;
+    final count = _editors.length;
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Remove all flagged questions?'),
+        content: Text(
+          'Remove all $count flagged question${count == 1 ? '' : 's'} from the deck? This cannot be undone.',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context, false),
+            child: const Text('Cancel'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.pop(context, true),
+            style: FilledButton.styleFrom(
+              backgroundColor: Theme.of(context).colorScheme.error,
+            ),
+            child: const Text('Remove all'),
+          ),
+        ],
+      ),
+    );
+    if (confirmed != true || !mounted) return;
+    final idsToRemove =
+        _editors.map((e) => e.originalId).whereType<String>().toSet();
+    final updatedQuestions =
+        _deck!.questions.where((q) => !idsToRemove.contains(q.id)).toList();
+    final updatedDeck = _deck!.copyWith(questions: updatedQuestions);
+    _deckStorage.saveDeckSync(updatedDeck);
+    for (final e in _editors) {
+      e.dispose();
+    }
+    setState(() {
+      _deck = updatedDeck;
+      _editors.clear();
+    });
+    showTopSnackBar(
+      context,
+      message: '$count question${count == 1 ? '' : 's'} removed from deck',
+      backgroundColor: Colors.green,
+    );
+  }
+
   void _save() {
     if (_deck == null) return;
     for (int i = 0; i < _editors.length; i++) {
@@ -94,8 +156,10 @@ class _FlaggedQuestionsScreenState extends State<FlaggedQuestionsScreen> {
       if (id == null) continue;
       final existing = questionMap[id];
       if (existing == null) continue;
+      final explanationText = editor.explanationController.text.trim();
       final updated = existing.copyWith(
         prompt: editor.promptController.text.trim(),
+        explanation: explanationText.isEmpty ? null : explanationText,
         answers: editor.answerControllers.map((c) => c.text.trim()).toList(),
         correctAnswerIndices: editor.correctAnswerIndices.toList()..sort(),
       );
@@ -141,6 +205,7 @@ class _FlaggedQuestionsScreenState extends State<FlaggedQuestionsScreen> {
     final list = questions.map((q) => {
       'id': q.id,
       'prompt': q.prompt,
+      if (q.explanation != null && q.explanation!.isNotEmpty) 'explanation': q.explanation,
       'answers': q.answers,
       'correctAnswerIndices': q.correctAnswerIndices,
     }).toList();
@@ -162,6 +227,11 @@ class _FlaggedQuestionsScreenState extends State<FlaggedQuestionsScreen> {
         title: Text('Flagged questions (${_editors.length})'),
         actions: [
           if (hasEditors) ...[
+            IconButton(
+              onPressed: _removeAllQuestions,
+              icon: const Icon(Icons.delete_forever),
+              tooltip: 'Remove all from deck',
+            ),
             IconButton(
               onPressed: _save,
               icon: const Icon(Icons.save),
@@ -216,7 +286,7 @@ class _FlaggedQuestionsScreenState extends State<FlaggedQuestionsScreen> {
                       key: ValueKey('flagged_${_editors[index].originalId}_$index'),
                       editor: _editors[index],
                       questionNumber: index + 1,
-                      onDelete: null,
+                      onDelete: () => _removeQuestion(index),
                       onUnflag: () => _unflag(index),
                       onChanged: () => setState(() {}),
                     );

lib/services/deck_storage.dart

@@ -66,6 +66,7 @@ class DeckStorage {
       'questions': deck.questions.map((q) => {
         'id': q.id,
         'prompt': q.prompt,
+        if (q.explanation != null && q.explanation!.isNotEmpty) 'explanation': q.explanation,
         'answers': q.answers,
         'correctAnswerIndices': q.correctAnswerIndices,
         'consecutiveCorrect': q.consecutiveCorrect,
@@ -133,6 +134,7 @@ class DeckStorage {
       return Question(
         id: questionMap['id'] as String? ?? '',
         prompt: questionMap['prompt'] as String? ?? '',
+        explanation: questionMap['explanation'] as String?,
         answers: (questionMap['answers'] as List<dynamic>?)
                 ?.map((e) => e.toString())
                 .toList() ??

packages/practice_engine/lib/logic/attempt_service.dart

@@ -80,29 +80,32 @@ class AttemptService {
           .firstOrNull ?? questionInAttempt;
 
       final userAnswer = answers[currentQuestion.id];
-      if (userAnswer == null) {
-        // Question not answered, treat as incorrect
-        continue;
-      }
 
-      // Handle both single answer (int) and multiple answers (List<int>)
+      // Not answering or invalid format: treat same as incorrect
       final List<int> userAnswerIndices;
-      if (userAnswer is int) {
+      final bool isCorrect;
+      if (userAnswer == null) {
+        userAnswerIndices = [];
+        isCorrect = false;
+      } else if (userAnswer is int) {
         userAnswerIndices = [userAnswer];
-      } else if (userAnswer is List<int>) {
-        userAnswerIndices = userAnswer;
-      } else {
-        // Invalid format, treat as incorrect
-        continue;
-      }
-
-      // Check if answer is correct
-      // For multiple correct answers: user must select all correct answers and no incorrect ones
         final correctIndices = currentQuestion.correctIndices;
         final userSet = userAnswerIndices.toSet();
         final correctSet = correctIndices.toSet();
-      final isCorrect = userSet.length == correctSet.length &&
+        isCorrect = userSet.length == correctSet.length &&
             userSet.every((idx) => correctSet.contains(idx));
+      } else if (userAnswer is List<int>) {
+        userAnswerIndices = userAnswer;
+        final correctIndices = currentQuestion.correctIndices;
+        final userSet = userAnswerIndices.toSet();
+        final correctSet = correctIndices.toSet();
+        isCorrect = userSet.length == correctSet.length &&
+            userSet.every((idx) => correctSet.contains(idx));
+      } else {
+        userAnswerIndices = [];
+        isCorrect = false;
+      }
+
       final userMarkedNeedsPractice = overrides[currentQuestion.id] ?? false;
 
       // Determine status change (from current deck state)

packages/practice_engine/lib/models/question.dart

@@ -6,6 +6,9 @@ class Question {
   /// The question prompt.
   final String prompt;
 
+  /// Optional explanation shown when viewing question details (e.g. after an attempt).
+  final String? explanation;
+
   /// List of possible answers.
   final List<String> answers;
 
@@ -42,6 +45,7 @@ class Question {
   Question({
     required this.id,
     required this.prompt,
+    this.explanation,
     required this.answers,
     List<int>? correctAnswerIndices,
     @Deprecated('Use correctAnswerIndices instead') int? correctAnswerIndex,
@@ -60,6 +64,7 @@ class Question {
   Question copyWith({
     String? id,
     String? prompt,
+    String? explanation,
     List<String>? answers,
     List<int>? correctAnswerIndices,
     @Deprecated('Use correctAnswerIndices instead') int? correctAnswerIndex,
@@ -74,6 +79,7 @@ class Question {
     return Question(
       id: id ?? this.id,
       prompt: prompt ?? this.prompt,
+      explanation: explanation ?? this.explanation,
       answers: answers ?? this.answers,
       correctAnswerIndices: correctAnswerIndices ?? this.correctAnswerIndices,
       correctAnswerIndex: correctAnswerIndex ?? this.correctAnswerIndex,
@@ -119,6 +125,7 @@ class Question {
           runtimeType == other.runtimeType &&
           id == other.id &&
           prompt == other.prompt &&
+          explanation == other.explanation &&
           answers.toString() == other.answers.toString() &&
           correctAnswerIndices.toString() == other.correctAnswerIndices.toString() &&
           consecutiveCorrect == other.consecutiveCorrect &&
@@ -133,6 +140,7 @@ class Question {
   int get hashCode =>
       id.hashCode ^
       prompt.hashCode ^
+      (explanation?.hashCode ?? 0) ^
       answers.hashCode ^
       correctAnswerIndices.hashCode ^
       consecutiveCorrect.hashCode ^