diff --git a/lib/function/friend_controller.dart b/lib/function/friend_controller.dart
new file mode 100644
index 0000000..6c24ba3
--- /dev/null
+++ b/lib/function/friend_controller.dart
@@ -0,0 +1,152 @@
+// 🧑‍🤝‍🧑 백품타 친구 목록/신청 화면의 기능(서버 통신/상태) 담당 컨트롤러.
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../config.dart';
+
+class FriendController extends ChangeNotifier {
+  final String studentId;
+  final String studentName;
+
+  FriendController({required this.studentId, required this.studentName});
+
+  bool _isLoading = true;
+  bool _isBusy = false;
+  List<dynamic> _friends = [];
+  List<dynamic> _requests = [];
+  bool _disposed = false;
+
+  bool get isLoading => _isLoading;
+  bool get isBusy => _isBusy;
+  List<dynamic> get friends => _friends;
+  List<dynamic> get requests => _requests;
+
+  void _safeNotify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  Future<void> init() async {
+    await refresh();
+  }
+
+  Future<void> refresh() async {
+    _isLoading = true;
+    _safeNotify();
+    await Future.wait([_fetchFriends(), _fetchRequests()]);
+    _isLoading = false;
+    _safeNotify();
+  }
+
+  Future<void> _fetchFriends() async {
+    try {
+      final response = await http.get(
+        Uri.parse('$baseUrl/api/friends/list?studentId=$studentId'),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _friends = data['friends'] ?? [];
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<void> _fetchRequests() async {
+    try {
+      final response = await http.get(
+        Uri.parse('$baseUrl/api/friends/requests?studentId=$studentId'),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _requests = data['requests'] ?? [];
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<(bool success, String message)> sendRequest(String friendId) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/friends/request'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({
+          "studentId": studentId,
+          "studentName": studentName,
+          "friendId": friendId.trim(),
+        }),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        return (true, '${result['message'] ?? '친구 신청을 보냈습니다.'}');
+      }
+      return (false, '${result['message'] ?? '친구 신청 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> respondRequest(
+    int requestId,
+    bool accept,
+  ) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/friends/respond'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({
+          "requestId": requestId,
+          "responderId": studentId,
+          "accept": accept,
+        }),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await refresh();
+        return (true, '${result['message'] ?? '처리했습니다.'}');
+      }
+      return (false, '${result['message'] ?? '처리 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> removeFriend(String friendId) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.delete(
+        Uri.parse('$baseUrl/api/friends'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({"studentId": studentId, "friendId": friendId}),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await _fetchFriends();
+        return (true, '${result['message'] ?? '삭제했습니다.'}');
+      }
+      return (false, '${result['message'] ?? '삭제 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+}
diff --git a/lib/function/group_controller.dart b/lib/function/group_controller.dart
new file mode 100644
index 0000000..95146c3
--- /dev/null
+++ b/lib/function/group_controller.dart
@@ -0,0 +1,124 @@
+// 👥 백품타 그룹 스터디(목록/생성/초대) 화면의 기능(서버 통신/상태) 담당 컨트롤러.
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../config.dart';
+
+class GroupController extends ChangeNotifier {
+  final String studentId;
+  final String studentName;
+
+  GroupController({required this.studentId, required this.studentName});
+
+  bool _isLoading = true;
+  bool _isBusy = false;
+  List<dynamic> _groups = [];
+  List<dynamic> _invites = [];
+  bool _disposed = false;
+
+  bool get isLoading => _isLoading;
+  bool get isBusy => _isBusy;
+  List<dynamic> get groups => _groups;
+  List<dynamic> get invites => _invites;
+
+  void _safeNotify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  Future<void> init() => refresh();
+
+  Future<void> refresh() async {
+    _isLoading = true;
+    _safeNotify();
+    await Future.wait([_fetchGroups(), _fetchInvites()]);
+    _isLoading = false;
+    _safeNotify();
+  }
+
+  Future<void> _fetchGroups() async {
+    try {
+      final response = await http.get(
+        Uri.parse('$baseUrl/api/groups/mine?studentId=$studentId'),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _groups = data['groups'] ?? [];
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<void> _fetchInvites() async {
+    try {
+      final response = await http.get(
+        Uri.parse('$baseUrl/api/groups/invites?studentId=$studentId'),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _invites = data['invites'] ?? [];
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<(bool success, String message)> createGroup(String name) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/groups'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({
+          "ownerId": studentId,
+          "ownerName": studentName,
+          "name": name.trim(),
+        }),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await _fetchGroups();
+        return (true, '${result['message'] ?? '그룹을 만들었습니다.'}');
+      }
+      return (false, '${result['message'] ?? '그룹 생성 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> respondInvite(
+    int inviteId,
+    bool accept,
+  ) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/groups/invites/$inviteId/respond'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({"responderId": studentId, "accept": accept}),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await refresh();
+        return (true, '${result['message'] ?? '처리했습니다.'}');
+      }
+      return (false, '${result['message'] ?? '처리 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+}
diff --git a/lib/function/group_detail_controller.dart b/lib/function/group_detail_controller.dart
new file mode 100644
index 0000000..fe7ff78
--- /dev/null
+++ b/lib/function/group_detail_controller.dart
@@ -0,0 +1,103 @@
+// 👥 백품타 그룹 상세(멤버/오늘 출석/초대/나가기) 화면의 기능 담당 컨트롤러.
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../config.dart';
+
+class GroupDetailController extends ChangeNotifier {
+  final int groupId;
+  final String studentId;
+
+  GroupDetailController({required this.groupId, required this.studentId});
+
+  bool _isLoading = true;
+  bool _isBusy = false;
+  List<dynamic> _members = [];
+  bool _disposed = false;
+
+  bool get isLoading => _isLoading;
+  bool get isBusy => _isBusy;
+  List<dynamic> get members => _members;
+
+  void _safeNotify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  Future<void> init() => refresh();
+
+  Future<void> refresh() async {
+    _isLoading = true;
+    _safeNotify();
+    try {
+      final response = await http.get(
+        Uri.parse('$baseUrl/api/groups/$groupId/members'),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _members = data['members'] ?? [];
+      }
+    } catch (_) {
+      // 조용히 무시
+    } finally {
+      _isLoading = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> invite(
+    String inviteeId,
+    String inviteeName,
+  ) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/groups/$groupId/invite'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({
+          "inviterId": studentId,
+          "inviteeId": inviteeId,
+          "inviteeName": inviteeName,
+        }),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        return (true, '${result['message'] ?? '초대를 보냈습니다.'}');
+      }
+      return (false, '${result['message'] ?? '초대 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> leave() async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/groups/$groupId/leave'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({"studentId": studentId}),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        return (true, '${result['message'] ?? '그룹에서 나갔습니다.'}');
+      }
+      return (false, '${result['message'] ?? '처리 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+}
diff --git a/lib/function/study_calendar_controller.dart b/lib/function/study_calendar_controller.dart
new file mode 100644
index 0000000..7293256
--- /dev/null
+++ b/lib/function/study_calendar_controller.dart
@@ -0,0 +1,150 @@
+// 📅 백품타 출석 달력(개인 스트릭 + 관리자 이벤트) 화면의 기능 담당 컨트롤러.
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../config.dart';
+
+class StudyCalendarController extends ChangeNotifier {
+  final String studentId;
+
+  StudyCalendarController({required this.studentId});
+
+  bool _isLoading = true;
+  bool _isBusy = false;
+  int _currentStreak = 0;
+  int _longestStreak = 0;
+  Set<String> _studiedDates = {};
+  Map<String, dynamic> _events = {}; // date -> {title, description}
+  DateTime _visibleMonth = DateTime.now();
+  bool _disposed = false;
+
+  bool get isLoading => _isLoading;
+  bool get isBusy => _isBusy;
+  int get currentStreak => _currentStreak;
+  int get longestStreak => _longestStreak;
+  Set<String> get studiedDates => _studiedDates;
+  Map<String, dynamic> get events => _events;
+  DateTime get visibleMonth => _visibleMonth;
+
+  void _safeNotify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  Future<void> init() => refresh();
+
+  Future<void> goToPreviousMonth() async {
+    _visibleMonth = DateTime(_visibleMonth.year, _visibleMonth.month - 1);
+    await refresh();
+  }
+
+  Future<void> goToNextMonth() async {
+    _visibleMonth = DateTime(_visibleMonth.year, _visibleMonth.month + 1);
+    await refresh();
+  }
+
+  Future<void> refresh() async {
+    _isLoading = true;
+    _safeNotify();
+    await Future.wait([_fetchStreak(), _fetchEvents()]);
+    _isLoading = false;
+    _safeNotify();
+  }
+
+  Future<void> _fetchStreak() async {
+    try {
+      final response = await http.get(
+        Uri.parse(
+          '$baseUrl/api/study/streak?studentId=$studentId'
+          '&year=${_visibleMonth.year}&month=${_visibleMonth.month}',
+        ),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        _currentStreak = (data['currentStreak'] as num?)?.toInt() ?? 0;
+        _longestStreak = (data['longestStreak'] as num?)?.toInt() ?? 0;
+        _studiedDates = ((data['studiedDates'] as List<dynamic>?) ?? [])
+            .map((d) => d.toString())
+            .toSet();
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<void> _fetchEvents() async {
+    try {
+      final response = await http.get(
+        Uri.parse(
+          '$baseUrl/api/calendar/events?year=${_visibleMonth.year}&month=${_visibleMonth.month}',
+        ),
+      );
+      if (response.statusCode == 200) {
+        final data = jsonDecode(utf8.decode(response.bodyBytes));
+        final List<dynamic> list = data['events'] ?? [];
+        _events = {for (final e in list) e['date']: e};
+      }
+    } catch (_) {
+      // 조용히 무시
+    }
+  }
+
+  Future<(bool success, String message)> saveEvent({
+    required String date,
+    required String title,
+    required String description,
+    required String createdBy,
+  }) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.post(
+        Uri.parse('$baseUrl/api/calendar/events'),
+        headers: {"Content-Type": "application/json"},
+        body: jsonEncode({
+          "date": date,
+          "title": title.trim(),
+          "description": description.trim(),
+          "createdBy": createdBy,
+        }),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await _fetchEvents();
+        return (true, '${result['message'] ?? '등록했습니다.'}');
+      }
+      return (false, '${result['message'] ?? '등록 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+
+  Future<(bool success, String message)> deleteEvent(String date) async {
+    _isBusy = true;
+    _safeNotify();
+    try {
+      final response = await http.delete(
+        Uri.parse('$baseUrl/api/calendar/events/$date'),
+      );
+      final result = jsonDecode(utf8.decode(response.bodyBytes));
+      if (response.statusCode == 200 && result['status'] == 'success') {
+        await _fetchEvents();
+        return (true, '${result['message'] ?? '삭제했습니다.'}');
+      }
+      return (false, '${result['message'] ?? '삭제 실패'}');
+    } catch (e) {
+      return (false, '네트워크 에러: $e');
+    } finally {
+      _isBusy = false;
+      _safeNotify();
+    }
+  }
+}
diff --git a/lib/ui/friends_screen.dart b/lib/ui/friends_screen.dart
new file mode 100644
index 0000000..2560e5d
--- /dev/null
+++ b/lib/ui/friends_screen.dart
@@ -0,0 +1,289 @@
+// 🧑‍🤝‍🧑 백품타 친구 화면 (UI 전용). "실시간 출석 현황"과 같은 패밀리룩을 따른다.
+// 서버 통신/상태는 lib/function/friend_controller.dart가 담당한다.
+import 'package:flutter/material.dart';
+import '../function/friend_controller.dart';
+import '../theme/app_palette.dart';
+import 'app_notice.dart';
+import 'title_pill.dart';
+
+class FriendsScreen extends StatefulWidget {
+  final String studentId;
+  final String studentName;
+
+  const FriendsScreen({
+    super.key,
+    required this.studentId,
+    required this.studentName,
+  });
+
+  @override
+  State<FriendsScreen> createState() => _FriendsScreenState();
+}
+
+class _FriendsScreenState extends State<FriendsScreen> {
+  late final FriendController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = FriendController(
+      studentId: widget.studentId,
+      studentName: widget.studentName,
+    );
+    _controller.init();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  Future<void> _showAddFriendDialog() async {
+    final idController = TextEditingController();
+    final result = await showDialog<bool>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: const Text('친구 추가'),
+        content: TextField(
+          controller: idController,
+          keyboardType: TextInputType.number,
+          decoration: const InputDecoration(
+            labelText: '친구 학번',
+            border: OutlineInputBorder(),
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, false),
+            child: const Text('취소', style: TextStyle(color: Colors.grey)),
+          ),
+          ElevatedButton(
+            style: ElevatedButton.styleFrom(
+              backgroundColor: AppPalette.ink,
+              foregroundColor: AppPalette.paper,
+            ),
+            onPressed: () => Navigator.pop(dialogContext, true),
+            child: const Text('신청하기'),
+          ),
+        ],
+      ),
+    );
+    if (result != true || idController.text.trim().isEmpty) return;
+    final (success, message) = await _controller.sendRequest(
+      idController.text.trim(),
+    );
+    if (!mounted) return;
+    AppNotice.show(
+      context,
+      message,
+      icon: success ? Icons.check_circle_rounded : Icons.error_outline_rounded,
+    );
+  }
+
+  Future<void> _respond(int requestId, bool accept) async {
+    final (_, message) = await _controller.respondRequest(requestId, accept);
+    if (!mounted) return;
+    AppNotice.show(context, message);
+  }
+
+  Future<void> _remove(String friendId) async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: const Text('친구 삭제'),
+        content: const Text('이 친구를 삭제하시겠습니까?'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, false),
+            child: const Text('취소', style: TextStyle(color: Colors.grey)),
+          ),
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, true),
+            child: const Text('삭제', style: TextStyle(color: Colors.red)),
+          ),
+        ],
+      ),
+    );
+    if (confirmed != true) return;
+    final (_, message) = await _controller.removeFriend(friendId);
+    if (!mounted) return;
+    AppNotice.show(context, message);
+  }
+
+  Widget _sectionHeader(String title, {int? count}) {
+    return Row(
+      children: [
+        Container(
+          width: 4,
+          height: 16,
+          decoration: BoxDecoration(
+            color: AppPalette.ink,
+            borderRadius: BorderRadius.circular(2),
+          ),
+        ),
+        const SizedBox(width: 8),
+        Text(
+          title,
+          style: const TextStyle(
+            fontSize: 16,
+            fontWeight: FontWeight.bold,
+            color: AppPalette.ink,
+          ),
+        ),
+        if (count != null) ...[
+          const SizedBox(width: 6),
+          Text(
+            '$count명',
+            style: TextStyle(fontSize: 13, color: Colors.grey[500]),
+          ),
+        ],
+      ],
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ListenableBuilder(
+      listenable: _controller,
+      builder: (context, _) {
+        return Scaffold(
+          backgroundColor: AppPalette.mist,
+          appBar: AppBar(
+            backgroundColor: Colors.transparent,
+            foregroundColor: AppPalette.ink,
+            elevation: 0,
+          ),
+          floatingActionButton: FloatingActionButton.extended(
+            backgroundColor: AppPalette.ink,
+            foregroundColor: AppPalette.paper,
+            onPressed: _showAddFriendDialog,
+            icon: const Icon(Icons.person_add_rounded),
+            label: const Text('친구 추가'),
+          ),
+          body: _controller.isLoading
+              ? const Center(child: CircularProgressIndicator())
+              : RefreshIndicator(
+                  onRefresh: _controller.refresh,
+                  child: ListView(
+                    padding: const EdgeInsets.fromLTRB(16, 0, 16, 90),
+                    children: [
+                      const Center(child: TitlePill('친구')),
+                      const SizedBox(height: 20),
+                      if (_controller.requests.isNotEmpty) ...[
+                        _sectionHeader(
+                          '받은 친구 신청',
+                          count: _controller.requests.length,
+                        ),
+                        const SizedBox(height: 10),
+                        for (final r in _controller.requests)
+                          Container(
+                            margin: const EdgeInsets.only(bottom: 8),
+                            padding: const EdgeInsets.symmetric(
+                              horizontal: 16,
+                              vertical: 12,
+                            ),
+                            decoration: BoxDecoration(
+                              color: AppPalette.paper,
+                              borderRadius: BorderRadius.circular(16),
+                              border: Border.all(color: AppPalette.sage),
+                            ),
+                            child: Row(
+                              children: [
+                                Expanded(
+                                  child: Text(
+                                    '${r['name']} (${r['studentId']})',
+                                    style: const TextStyle(
+                                      fontWeight: FontWeight.bold,
+                                    ),
+                                  ),
+                                ),
+                                TextButton(
+                                  onPressed: () =>
+                                      _respond(r['requestId'] as int, false),
+                                  child: const Text(
+                                    '거절',
+                                    style: TextStyle(color: Colors.grey),
+                                  ),
+                                ),
+                                ElevatedButton(
+                                  style: ElevatedButton.styleFrom(
+                                    backgroundColor: AppPalette.ink,
+                                    foregroundColor: AppPalette.paper,
+                                  ),
+                                  onPressed: () =>
+                                      _respond(r['requestId'] as int, true),
+                                  child: const Text('수락'),
+                                ),
+                              ],
+                            ),
+                          ),
+                        const SizedBox(height: 20),
+                      ],
+                      _sectionHeader('내 친구', count: _controller.friends.length),
+                      const SizedBox(height: 10),
+                      if (_controller.friends.isEmpty)
+                        const Padding(
+                          padding: EdgeInsets.symmetric(vertical: 12),
+                          child: Text(
+                            '아직 친구가 없어요. 학번으로 친구를 추가해보세요.',
+                            style: TextStyle(color: Colors.grey),
+                          ),
+                        )
+                      else
+                        for (final f in _controller.friends)
+                          Container(
+                            margin: const EdgeInsets.only(bottom: 8),
+                            padding: const EdgeInsets.symmetric(
+                              horizontal: 16,
+                              vertical: 12,
+                            ),
+                            decoration: BoxDecoration(
+                              color: AppPalette.paper,
+                              borderRadius: BorderRadius.circular(16),
+                              border: Border.all(color: AppPalette.sage),
+                            ),
+                            child: Row(
+                              children: [
+                                Container(
+                                  padding: const EdgeInsets.all(6),
+                                  decoration: BoxDecoration(
+                                    color: AppPalette.ink.withValues(
+                                      alpha: 0.06,
+                                    ),
+                                    shape: BoxShape.circle,
+                                  ),
+                                  child: const Icon(
+                                    Icons.person_rounded,
+                                    size: 16,
+                                    color: AppPalette.ink,
+                                  ),
+                                ),
+                                const SizedBox(width: 10),
+                                Expanded(
+                                  child: Text(
+                                    '${f['name']} (${f['studentId']})',
+                                    style: const TextStyle(
+                                      fontWeight: FontWeight.bold,
+                                    ),
+                                  ),
+                                ),
+                                IconButton(
+                                  icon: const Icon(
+                                    Icons.person_remove_outlined,
+                                    color: Colors.grey,
+                                  ),
+                                  onPressed: () =>
+                                      _remove(f['studentId'] as String),
+                                ),
+                              ],
+                            ),
+                          ),
+                    ],
+                  ),
+                ),
+        );
+      },
+    );
+  }
+}
diff --git a/lib/ui/group_detail_screen.dart b/lib/ui/group_detail_screen.dart
new file mode 100644
index 0000000..803573d
--- /dev/null
+++ b/lib/ui/group_detail_screen.dart
@@ -0,0 +1,316 @@
+// 👥 백품타 그룹 상세 화면 (UI 전용) - 멤버 오늘 출석 현황, 친구 초대, 그룹 나가기.
+// 서버 통신/상태는 lib/function/group_detail_controller.dart, friend_controller.dart가 담당한다.
+import 'package:flutter/material.dart';
+import '../function/friend_controller.dart';
+import '../function/group_detail_controller.dart';
+import '../theme/app_palette.dart';
+import 'app_notice.dart';
+import 'title_pill.dart';
+
+class GroupDetailScreen extends StatefulWidget {
+  final int groupId;
+  final String groupName;
+  final String studentId;
+
+  const GroupDetailScreen({
+    super.key,
+    required this.groupId,
+    required this.groupName,
+    required this.studentId,
+  });
+
+  @override
+  State<GroupDetailScreen> createState() => _GroupDetailScreenState();
+}
+
+class _GroupDetailScreenState extends State<GroupDetailScreen> {
+  late final GroupDetailController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = GroupDetailController(
+      groupId: widget.groupId,
+      studentId: widget.studentId,
+    );
+    _controller.init();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  Future<void> _showInviteSheet() async {
+    final friendController = FriendController(
+      studentId: widget.studentId,
+      studentName: '',
+    );
+    await friendController.init();
+    if (!mounted) return;
+
+    final memberIds = _controller.members
+        .map((m) => m['studentId'] as String)
+        .toSet();
+    final invitable = friendController.friends
+        .where((f) => !memberIds.contains(f['studentId']))
+        .toList();
+
+    await showModalBottomSheet<void>(
+      context: context,
+      backgroundColor: AppPalette.paper,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
+      ),
+      builder: (sheetContext) {
+        return Padding(
+          padding: const EdgeInsets.all(20),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              const Text(
+                '친구 초대',
+                style: TextStyle(fontWeight: FontWeight.bold, fontSize: 16),
+              ),
+              const SizedBox(height: 12),
+              if (invitable.isEmpty)
+                const Padding(
+                  padding: EdgeInsets.symmetric(vertical: 16),
+                  child: Text(
+                    '초대할 수 있는 친구가 없어요.\n(이미 그룹에 있거나 친구가 없어요)',
+                    textAlign: TextAlign.center,
+                    style: TextStyle(color: Colors.grey),
+                  ),
+                )
+              else
+                ConstrainedBox(
+                  constraints: const BoxConstraints(maxHeight: 320),
+                  child: ListView(
+                    shrinkWrap: true,
+                    children: [
+                      for (final f in invitable)
+                        ListTile(
+                          leading: const Icon(
+                            Icons.person_rounded,
+                            color: AppPalette.ink,
+                          ),
+                          title: Text('${f['name']}'),
+                          subtitle: Text('${f['studentId']}'),
+                          trailing: ElevatedButton(
+                            style: ElevatedButton.styleFrom(
+                              backgroundColor: AppPalette.ink,
+                              foregroundColor: AppPalette.paper,
+                            ),
+                            onPressed: () async {
+                              final (success, message) = await _controller
+                                  .invite(
+                                    f['studentId'] as String,
+                                    f['name'] as String,
+                                  );
+                              if (sheetContext.mounted) {
+                                Navigator.of(sheetContext).pop();
+                              }
+                              if (!mounted) return;
+                              AppNotice.show(
+                                context,
+                                message,
+                                icon: success
+                                    ? Icons.check_circle_rounded
+                                    : Icons.error_outline_rounded,
+                              );
+                            },
+                            child: const Text('초대'),
+                          ),
+                        ),
+                    ],
+                  ),
+                ),
+            ],
+          ),
+        );
+      },
+    );
+    friendController.dispose();
+  }
+
+  Future<void> _leave() async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: const Text('그룹 나가기'),
+        content: Text('${widget.groupName} 그룹에서 나가시겠습니까?'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, false),
+            child: const Text('취소', style: TextStyle(color: Colors.grey)),
+          ),
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, true),
+            child: const Text('나가기', style: TextStyle(color: Colors.red)),
+          ),
+        ],
+      ),
+    );
+    if (confirmed != true) return;
+    final (success, message) = await _controller.leave();
+    if (!mounted) return;
+    AppNotice.show(context, message);
+    if (success) Navigator.of(context).pop();
+  }
+
+  String _formatMinutes(int seconds) {
+    final m = seconds ~/ 60;
+    if (m < 60) return '$m분';
+    return '${m ~/ 60}시간 ${m % 60}분';
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ListenableBuilder(
+      listenable: _controller,
+      builder: (context, _) {
+        final members = _controller.members;
+        final attendedCount = members
+            .where((m) => m['attendedToday'] == true)
+            .length;
+
+        return Scaffold(
+          backgroundColor: AppPalette.mist,
+          appBar: AppBar(
+            backgroundColor: Colors.transparent,
+            foregroundColor: AppPalette.ink,
+            elevation: 0,
+            actions: [
+              IconButton(
+                icon: const Icon(Icons.exit_to_app_rounded),
+                tooltip: '그룹 나가기',
+                onPressed: _leave,
+              ),
+            ],
+          ),
+          floatingActionButton: FloatingActionButton.extended(
+            backgroundColor: AppPalette.ink,
+            foregroundColor: AppPalette.paper,
+            onPressed: _showInviteSheet,
+            icon: const Icon(Icons.person_add_rounded),
+            label: const Text('친구 초대'),
+          ),
+          body: _controller.isLoading
+              ? const Center(child: CircularProgressIndicator())
+              : RefreshIndicator(
+                  onRefresh: _controller.refresh,
+                  child: ListView(
+                    padding: const EdgeInsets.fromLTRB(16, 0, 16, 90),
+                    children: [
+                      Center(child: TitlePill(widget.groupName)),
+                      const SizedBox(height: 16),
+                      Row(
+                        children: [
+                          Expanded(child: _statPill('전체 멤버', members.length)),
+                          const SizedBox(width: 8),
+                          Expanded(child: _statPill('오늘 공부함', attendedCount)),
+                        ],
+                      ),
+                      const SizedBox(height: 20),
+                      Row(
+                        children: [
+                          Container(
+                            width: 4,
+                            height: 16,
+                            decoration: BoxDecoration(
+                              color: AppPalette.ink,
+                              borderRadius: BorderRadius.circular(2),
+                            ),
+                          ),
+                          const SizedBox(width: 8),
+                          const Text(
+                            '오늘 출석 현황',
+                            style: TextStyle(
+                              fontSize: 16,
+                              fontWeight: FontWeight.bold,
+                              color: AppPalette.ink,
+                            ),
+                          ),
+                        ],
+                      ),
+                      const SizedBox(height: 10),
+                      for (final m in members)
+                        Container(
+                          margin: const EdgeInsets.only(bottom: 8),
+                          padding: const EdgeInsets.symmetric(
+                            horizontal: 16,
+                            vertical: 12,
+                          ),
+                          decoration: BoxDecoration(
+                            color: AppPalette.paper,
+                            borderRadius: BorderRadius.circular(16),
+                            border: Border.all(color: AppPalette.sage),
+                          ),
+                          child: Row(
+                            children: [
+                              Icon(
+                                m['attendedToday'] == true
+                                    ? Icons.check_circle_rounded
+                                    : Icons.radio_button_unchecked_rounded,
+                                color: m['attendedToday'] == true
+                                    ? AppPalette.ink
+                                    : Colors.grey[350],
+                                size: 20,
+                              ),
+                              const SizedBox(width: 10),
+                              Expanded(
+                                child: Text(
+                                  '${m['name']}'
+                                  '${m['role'] == 'owner' ? ' (그룹장)' : ''}',
+                                  style: const TextStyle(
+                                    fontWeight: FontWeight.bold,
+                                  ),
+                                ),
+                              ),
+                              Text(
+                                _formatMinutes(
+                                  (m['todaySeconds'] as num?)?.toInt() ?? 0,
+                                ),
+                                style: TextStyle(
+                                  color: Colors.grey[500],
+                                  fontSize: 12,
+                                ),
+                              ),
+                            ],
+                          ),
+                        ),
+                    ],
+                  ),
+                ),
+        );
+      },
+    );
+  }
+
+  Widget _statPill(String label, int count) {
+    return Container(
+      padding: const EdgeInsets.symmetric(vertical: 14, horizontal: 16),
+      decoration: BoxDecoration(
+        color: AppPalette.paper,
+        borderRadius: BorderRadius.circular(28),
+        border: Border.all(color: AppPalette.sage),
+      ),
+      child: Column(
+        children: [
+          Text(label, style: TextStyle(fontSize: 12, color: Colors.grey[600])),
+          const SizedBox(height: 4),
+          Text(
+            '$count명',
+            style: const TextStyle(
+              fontSize: 18,
+              fontWeight: FontWeight.bold,
+              color: AppPalette.ink,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
diff --git a/lib/ui/group_list_screen.dart b/lib/ui/group_list_screen.dart
new file mode 100644
index 0000000..0f46923
--- /dev/null
+++ b/lib/ui/group_list_screen.dart
@@ -0,0 +1,304 @@
+// 👥 백품타 그룹 스터디 목록 화면 (UI 전용). "실시간 출석 현황"과 같은 패밀리룩을 따른다.
+// 서버 통신/상태는 lib/function/group_controller.dart가 담당한다.
+import 'package:flutter/material.dart';
+import '../function/group_controller.dart';
+import '../theme/app_palette.dart';
+import 'app_notice.dart';
+import 'group_detail_screen.dart';
+import 'launchpad_transition.dart';
+import 'title_pill.dart';
+
+class GroupListScreen extends StatefulWidget {
+  final String studentId;
+  final String studentName;
+
+  const GroupListScreen({
+    super.key,
+    required this.studentId,
+    required this.studentName,
+  });
+
+  @override
+  State<GroupListScreen> createState() => _GroupListScreenState();
+}
+
+class _GroupListScreenState extends State<GroupListScreen> {
+  late final GroupController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = GroupController(
+      studentId: widget.studentId,
+      studentName: widget.studentName,
+    );
+    _controller.init();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  Future<void> _showCreateGroupDialog() async {
+    final nameController = TextEditingController();
+    final result = await showDialog<bool>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: const Text('그룹 만들기'),
+        content: TextField(
+          controller: nameController,
+          maxLength: 20,
+          decoration: const InputDecoration(
+            labelText: '그룹 이름',
+            border: OutlineInputBorder(),
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext, false),
+            child: const Text('취소', style: TextStyle(color: Colors.grey)),
+          ),
+          ElevatedButton(
+            style: ElevatedButton.styleFrom(
+              backgroundColor: AppPalette.ink,
+              foregroundColor: AppPalette.paper,
+            ),
+            onPressed: () => Navigator.pop(dialogContext, true),
+            child: const Text('만들기'),
+          ),
+        ],
+      ),
+    );
+    if (result != true || nameController.text.trim().isEmpty) return;
+    final (success, message) = await _controller.createGroup(
+      nameController.text.trim(),
+    );
+    if (!mounted) return;
+    AppNotice.show(
+      context,
+      message,
+      icon: success ? Icons.check_circle_rounded : Icons.error_outline_rounded,
+    );
+  }
+
+  Future<void> _respondInvite(int inviteId, bool accept) async {
+    final (_, message) = await _controller.respondInvite(inviteId, accept);
+    if (!mounted) return;
+    AppNotice.show(context, message);
+  }
+
+  Future<void> _openGroup(dynamic group) async {
+    await pushLaunchpad(
+      context,
+      (context) => GroupDetailScreen(
+        groupId: group['groupId'] as int,
+        groupName: group['name'] as String,
+        studentId: widget.studentId,
+      ),
+    );
+    _controller.refresh();
+  }
+
+  Widget _sectionHeader(String title, {int? count}) {
+    return Row(
+      children: [
+        Container(
+          width: 4,
+          height: 16,
+          decoration: BoxDecoration(
+            color: AppPalette.ink,
+            borderRadius: BorderRadius.circular(2),
+          ),
+        ),
+        const SizedBox(width: 8),
+        Text(
+          title,
+          style: const TextStyle(
+            fontSize: 16,
+            fontWeight: FontWeight.bold,
+            color: AppPalette.ink,
+          ),
+        ),
+        if (count != null) ...[
+          const SizedBox(width: 6),
+          Text(
+            '$count개',
+            style: TextStyle(fontSize: 13, color: Colors.grey[500]),
+          ),
+        ],
+      ],
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ListenableBuilder(
+      listenable: _controller,
+      builder: (context, _) {
+        return Scaffold(
+          backgroundColor: AppPalette.mist,
+          appBar: AppBar(
+            backgroundColor: Colors.transparent,
+            foregroundColor: AppPalette.ink,
+            elevation: 0,
+          ),
+          floatingActionButton: FloatingActionButton.extended(
+            backgroundColor: AppPalette.ink,
+            foregroundColor: AppPalette.paper,
+            onPressed: _showCreateGroupDialog,
+            icon: const Icon(Icons.add_rounded),
+            label: const Text('그룹 만들기'),
+          ),
+          body: _controller.isLoading
+              ? const Center(child: CircularProgressIndicator())
+              : RefreshIndicator(
+                  onRefresh: _controller.refresh,
+                  child: ListView(
+                    padding: const EdgeInsets.fromLTRB(16, 0, 16, 90),
+                    children: [
+                      const Center(child: TitlePill('그룹 스터디')),
+                      const SizedBox(height: 20),
+                      if (_controller.invites.isNotEmpty) ...[
+                        _sectionHeader(
+                          '받은 그룹 초대',
+                          count: _controller.invites.length,
+                        ),
+                        const SizedBox(height: 10),
+                        for (final inv in _controller.invites)
+                          Container(
+                            margin: const EdgeInsets.only(bottom: 8),
+                            padding: const EdgeInsets.symmetric(
+                              horizontal: 16,
+                              vertical: 12,
+                            ),
+                            decoration: BoxDecoration(
+                              color: AppPalette.paper,
+                              borderRadius: BorderRadius.circular(16),
+                              border: Border.all(color: AppPalette.sage),
+                            ),
+                            child: Row(
+                              children: [
+                                Expanded(
+                                  child: Text(
+                                    '${inv['groupName']}',
+                                    style: const TextStyle(
+                                      fontWeight: FontWeight.bold,
+                                    ),
+                                  ),
+                                ),
+                                TextButton(
+                                  onPressed: () => _respondInvite(
+                                    inv['inviteId'] as int,
+                                    false,
+                                  ),
+                                  child: const Text(
+                                    '거절',
+                                    style: TextStyle(color: Colors.grey),
+                                  ),
+                                ),
+                                ElevatedButton(
+                                  style: ElevatedButton.styleFrom(
+                                    backgroundColor: AppPalette.ink,
+                                    foregroundColor: AppPalette.paper,
+                                  ),
+                                  onPressed: () => _respondInvite(
+                                    inv['inviteId'] as int,
+                                    true,
+                                  ),
+                                  child: const Text('참여'),
+                                ),
+                              ],
+                            ),
+                          ),
+                        const SizedBox(height: 20),
+                      ],
+                      _sectionHeader('내 그룹', count: _controller.groups.length),
+                      const SizedBox(height: 10),
+                      if (_controller.groups.isEmpty)
+                        const Padding(
+                          padding: EdgeInsets.symmetric(vertical: 12),
+                          child: Text(
+                            '아직 그룹이 없어요. 새 그룹을 만들거나 초대를 기다려보세요.',
+                            style: TextStyle(color: Colors.grey),
+                          ),
+                        )
+                      else
+                        for (final g in _controller.groups)
+                          GestureDetector(
+                            onTap: () => _openGroup(g),
+                            child: Container(
+                              margin: const EdgeInsets.only(bottom: 8),
+                              padding: const EdgeInsets.symmetric(
+                                horizontal: 16,
+                                vertical: 14,
+                              ),
+                              decoration: BoxDecoration(
+                                color: AppPalette.paper,
+                                borderRadius: BorderRadius.circular(16),
+                                border: Border.all(color: AppPalette.sage),
+                                boxShadow: [
+                                  BoxShadow(
+                                    color: Colors.black.withValues(alpha: 0.03),
+                                    blurRadius: 12,
+                                    offset: const Offset(0, 4),
+                                  ),
+                                ],
+                              ),
+                              child: Row(
+                                children: [
+                                  Container(
+                                    padding: const EdgeInsets.all(8),
+                                    decoration: BoxDecoration(
+                                      color: AppPalette.ink.withValues(
+                                        alpha: 0.06,
+                                      ),
+                                      shape: BoxShape.circle,
+                                    ),
+                                    child: const Icon(
+                                      Icons.groups_rounded,
+                                      color: AppPalette.ink,
+                                      size: 18,
+                                    ),
+                                  ),
+                                  const SizedBox(width: 12),
+                                  Expanded(
+                                    child: Column(
+                                      crossAxisAlignment:
+                                          CrossAxisAlignment.start,
+                                      children: [
+                                        Text(
+                                          '${g['name']}',
+                                          style: const TextStyle(
+                                            fontWeight: FontWeight.bold,
+                                            fontSize: 15,
+                                          ),
+                                        ),
+                                        Text(
+                                          '멤버 ${g['memberCount']}명'
+                                          '${g['isOwner'] == true ? ' · 그룹장' : ''}',
+                                          style: TextStyle(
+                                            fontSize: 12,
+                                            color: Colors.grey[500],
+                                          ),
+                                        ),
+                                      ],
+                                    ),
+                                  ),
+                                  const Icon(
+                                    Icons.chevron_right_rounded,
+                                    color: Colors.grey,
+                                  ),
+                                ],
+                              ),
+                            ),
+                          ),
+                    ],
+                  ),
+                ),
+        );
+      },
+    );
+  }
+}
diff --git a/lib/ui/main_dashboard.dart b/lib/ui/main_dashboard.dart
index 439ba18..1c86dc4 100644
--- a/lib/ui/main_dashboard.dart
+++ b/lib/ui/main_dashboard.dart
@@ -17,10 +17,13 @@ import 'board_report_screen.dart';
 import 'dashboard_settings_page.dart';
 import 'device_checkout_ledger_page.dart';
 import 'device_checkout_request_screen.dart';
+import 'friends_screen.dart';
+import 'group_list_screen.dart';
 import 'launchpad_transition.dart';
 import 'login_screen.dart';
 import 'nfc_poccket_checkin_screen.dart';
 import 'nfc_tag_writer_screen.dart';
+import 'study_calendar_screen.dart';
 import 'study_timer_screen.dart';
 import 'teacher_attendance_page.dart';
 import 'teacher_call_screen.dart';
@@ -365,6 +368,49 @@ class _MainDashboardState extends State<MainDashboard> {
           ),
         ),
       ));
+      tiles.add((
+        id: 'friends',
+        child: _buildModernCard(
+          icon: Icons.people_alt_rounded,
+          title: '친구',
+          subtitle: '학번으로 친구 추가',
+          color: AppPalette.ink,
+          onTap: () => pushLaunchpad(
+            context,
+            (context) =>
+                FriendsScreen(studentId: _displayId, studentName: _displayName),
+          ),
+        ),
+      ));
+      tiles.add((
+        id: 'group_study',
+        child: _buildModernCard(
+          icon: Icons.groups_rounded,
+          title: '그룹 스터디',
+          subtitle: '친구랑 그룹 만들어 같이 공부',
+          color: AppPalette.ink,
+          onTap: () => pushLaunchpad(
+            context,
+            (context) => GroupListScreen(
+              studentId: _displayId,
+              studentName: _displayName,
+            ),
+          ),
+        ),
+      ));
+      tiles.add((
+        id: 'study_calendar',
+        child: _buildModernCard(
+          icon: Icons.calendar_month_rounded,
+          title: '출석 달력',
+          subtitle: '연속 출석 기록 확인',
+          color: AppPalette.ink,
+          onTap: () => pushLaunchpad(
+            context,
+            (context) => StudyCalendarScreen(studentId: _displayId),
+          ),
+        ),
+      ));
     }
 
     if (_isTeacherOrAbove) {
@@ -423,6 +469,22 @@ class _MainDashboardState extends State<MainDashboard> {
           ),
         ),
       ));
+      tiles.add((
+        id: 'study_calendar_admin',
+        child: _buildModernCard(
+          icon: Icons.event_available_rounded,
+          title: '출석 달력 관리',
+          subtitle: '날짜별 선물/이벤트 등록',
+          color: AppPalette.ink,
+          onTap: () => pushLaunchpad(
+            context,
+            (context) => StudyCalendarScreen(
+              studentId: _displayId,
+              canManageEvents: true,
+            ),
+          ),
+        ),
+      ));
       tiles.add((
         id: 'teacher_location',
         child: _buildModernCard(
diff --git a/lib/ui/study_calendar_screen.dart b/lib/ui/study_calendar_screen.dart
new file mode 100644
index 0000000..9b1404d
--- /dev/null
+++ b/lib/ui/study_calendar_screen.dart
@@ -0,0 +1,404 @@
+// 📅 백품타 출석 달력 화면 (UI 전용) - 개인 연속출석(스트릭) + 관리자 이벤트 달력.
+// "실시간 출석 현황"과 같은 패밀리룩(제목 알약 + 필 통계 + 둥근 카드)을 따른다.
+// 서버 통신/상태는 lib/function/study_calendar_controller.dart가 담당한다.
+import 'package:flutter/material.dart';
+import '../function/study_calendar_controller.dart';
+import '../theme/app_palette.dart';
+import 'app_notice.dart';
+import 'title_pill.dart';
+
+class StudyCalendarScreen extends StatefulWidget {
+  final String studentId;
+  final bool canManageEvents;
+
+  const StudyCalendarScreen({
+    super.key,
+    required this.studentId,
+    this.canManageEvents = false,
+  });
+
+  @override
+  State<StudyCalendarScreen> createState() => _StudyCalendarScreenState();
+}
+
+class _StudyCalendarScreenState extends State<StudyCalendarScreen> {
+  late final StudyCalendarController _controller;
+  static const _weekdayLabels = ['일', '월', '화', '수', '목', '금', '토'];
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = StudyCalendarController(studentId: widget.studentId);
+    _controller.init();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  String _dateKey(DateTime d) =>
+      '${d.year.toString().padLeft(4, '0')}-${d.month.toString().padLeft(2, '0')}-${d.day.toString().padLeft(2, '0')}';
+
+  Future<void> _onDayTap(DateTime day) async {
+    final key = _dateKey(day);
+    final event = _controller.events[key];
+
+    if (!widget.canManageEvents) {
+      if (event != null) {
+        await showDialog<void>(
+          context: context,
+          builder: (dialogContext) => AlertDialog(
+            title: Text(event['title'] ?? ''),
+            content: Text(
+              (event['description'] ?? '').toString().isEmpty
+                  ? '등록된 설명이 없어요.'
+                  : event['description'],
+            ),
+            actions: [
+              TextButton(
+                onPressed: () => Navigator.pop(dialogContext),
+                child: const Text('닫기'),
+              ),
+            ],
+          ),
+        );
+      }
+      return;
+    }
+
+    final titleController = TextEditingController(text: event?['title'] ?? '');
+    final descController = TextEditingController(
+      text: event?['description'] ?? '',
+    );
+
+    await showModalBottomSheet<void>(
+      context: context,
+      isScrollControlled: true,
+      backgroundColor: AppPalette.paper,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
+      ),
+      builder: (sheetContext) {
+        return Padding(
+          padding: EdgeInsets.only(
+            left: 20,
+            right: 20,
+            top: 20,
+            bottom: MediaQuery.of(sheetContext).viewInsets.bottom + 20,
+          ),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              Text(
+                '$key 이벤트',
+                style: const TextStyle(
+                  fontWeight: FontWeight.bold,
+                  fontSize: 16,
+                ),
+              ),
+              const SizedBox(height: 12),
+              TextField(
+                controller: titleController,
+                maxLength: 30,
+                decoration: InputDecoration(
+                  hintText: '제목 (예: 기프티콘 이벤트)',
+                  filled: true,
+                  fillColor: AppPalette.mist,
+                  border: OutlineInputBorder(
+                    borderRadius: BorderRadius.circular(12),
+                    borderSide: BorderSide.none,
+                  ),
+                ),
+              ),
+              TextField(
+                controller: descController,
+                maxLength: 100,
+                maxLines: 3,
+                decoration: InputDecoration(
+                  hintText: '설명 (선택)',
+                  filled: true,
+                  fillColor: AppPalette.mist,
+                  border: OutlineInputBorder(
+                    borderRadius: BorderRadius.circular(12),
+                    borderSide: BorderSide.none,
+                  ),
+                ),
+              ),
+              const SizedBox(height: 12),
+              Row(
+                children: [
+                  if (event != null)
+                    Expanded(
+                      child: OutlinedButton(
+                        onPressed: () async {
+                          final (success, message) = await _controller
+                              .deleteEvent(key);
+                          if (sheetContext.mounted) {
+                            Navigator.of(sheetContext).pop();
+                          }
+                          if (!mounted) return;
+                          AppNotice.show(context, message);
+                        },
+                        child: const Text(
+                          '삭제',
+                          style: TextStyle(color: Colors.red),
+                        ),
+                      ),
+                    ),
+                  if (event != null) const SizedBox(width: 8),
+                  Expanded(
+                    child: ElevatedButton(
+                      style: ElevatedButton.styleFrom(
+                        backgroundColor: AppPalette.ink,
+                        foregroundColor: AppPalette.paper,
+                      ),
+                      onPressed: () async {
+                        if (titleController.text.trim().isEmpty) return;
+                        final (success, message) = await _controller.saveEvent(
+                          date: key,
+                          title: titleController.text,
+                          description: descController.text,
+                          createdBy: widget.studentId,
+                        );
+                        if (sheetContext.mounted) {
+                          Navigator.of(sheetContext).pop();
+                        }
+                        if (!mounted) return;
+                        AppNotice.show(
+                          context,
+                          message,
+                          icon: success
+                              ? Icons.check_circle_rounded
+                              : Icons.error_outline_rounded,
+                        );
+                      },
+                      child: const Text('저장'),
+                    ),
+                  ),
+                ],
+              ),
+            ],
+          ),
+        );
+      },
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ListenableBuilder(
+      listenable: _controller,
+      builder: (context, _) {
+        final month = _controller.visibleMonth;
+        final firstOfMonth = DateTime(month.year, month.month, 1);
+        final daysInMonth = DateTime(month.year, month.month + 1, 0).day;
+        final leadingBlanks = firstOfMonth.weekday % 7;
+        final today = DateTime.now();
+
+        return Scaffold(
+          backgroundColor: AppPalette.mist,
+          appBar: AppBar(
+            backgroundColor: Colors.transparent,
+            foregroundColor: AppPalette.ink,
+            elevation: 0,
+          ),
+          body: _controller.isLoading
+              ? const Center(child: CircularProgressIndicator())
+              : ListView(
+                  padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
+                  children: [
+                    const Center(child: TitlePill('출석 달력')),
+                    const SizedBox(height: 16),
+                    Row(
+                      children: [
+                        Expanded(
+                          child: _statPill('연속 출석', _controller.currentStreak),
+                        ),
+                        const SizedBox(width: 8),
+                        Expanded(
+                          child: _statPill('최장 기록', _controller.longestStreak),
+                        ),
+                      ],
+                    ),
+                    const SizedBox(height: 20),
+                    Row(
+                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                      children: [
+                        IconButton(
+                          icon: const Icon(Icons.chevron_left_rounded),
+                          onPressed: _controller.goToPreviousMonth,
+                        ),
+                        Text(
+                          '${month.year}년 ${month.month}월',
+                          style: const TextStyle(
+                            fontWeight: FontWeight.bold,
+                            fontSize: 16,
+                          ),
+                        ),
+                        IconButton(
+                          icon: const Icon(Icons.chevron_right_rounded),
+                          onPressed: _controller.goToNextMonth,
+                        ),
+                      ],
+                    ),
+                    const SizedBox(height: 8),
+                    Row(
+                      children: [
+                        for (final label in _weekdayLabels)
+                          Expanded(
+                            child: Center(
+                              child: Text(
+                                label,
+                                style: TextStyle(
+                                  color: Colors.grey[500],
+                                  fontSize: 12,
+                                  fontWeight: FontWeight.bold,
+                                ),
+                              ),
+                            ),
+                          ),
+                      ],
+                    ),
+                    const SizedBox(height: 6),
+                    GridView.builder(
+                      shrinkWrap: true,
+                      physics: const NeverScrollableScrollPhysics(),
+                      gridDelegate:
+                          const SliverGridDelegateWithFixedCrossAxisCount(
+                            crossAxisCount: 7,
+                            mainAxisSpacing: 6,
+                            crossAxisSpacing: 6,
+                            childAspectRatio: 0.85,
+                          ),
+                      itemCount: leadingBlanks + daysInMonth,
+                      itemBuilder: (context, index) {
+                        if (index < leadingBlanks) {
+                          return const SizedBox.shrink();
+                        }
+                        final day = index - leadingBlanks + 1;
+                        final date = DateTime(month.year, month.month, day);
+                        final key = _dateKey(date);
+                        final studied = _controller.studiedDates.contains(key);
+                        final event = _controller.events[key];
+                        final isToday =
+                            date.year == today.year &&
+                            date.month == today.month &&
+                            date.day == today.day;
+
+                        return GestureDetector(
+                          onTap: () => _onDayTap(date),
+                          child: Container(
+                            decoration: BoxDecoration(
+                              color: studied
+                                  ? AppPalette.ink
+                                  : AppPalette.paper,
+                              borderRadius: BorderRadius.circular(12),
+                              border: Border.all(
+                                color: isToday
+                                    ? AppPalette.ink
+                                    : AppPalette.sage,
+                                width: isToday ? 2 : 1,
+                              ),
+                            ),
+                            child: Stack(
+                              children: [
+                                Center(
+                                  child: Text(
+                                    '$day',
+                                    style: TextStyle(
+                                      fontWeight: FontWeight.bold,
+                                      color: studied
+                                          ? Colors.white
+                                          : AppPalette.ink,
+                                    ),
+                                  ),
+                                ),
+                                if (event != null)
+                                  Positioned(
+                                    top: 3,
+                                    right: 3,
+                                    child: Icon(
+                                      Icons.card_giftcard_rounded,
+                                      size: 12,
+                                      color: studied
+                                          ? Colors.white
+                                          : Colors.orange,
+                                    ),
+                                  ),
+                              ],
+                            ),
+                          ),
+                        );
+                      },
+                    ),
+                    const SizedBox(height: 16),
+                    Row(
+                      children: [
+                        _legendDot(AppPalette.ink, '공부한 날'),
+                        const SizedBox(width: 16),
+                        _legendIcon(
+                          Icons.card_giftcard_rounded,
+                          Colors.orange,
+                          '이벤트',
+                        ),
+                      ],
+                    ),
+                  ],
+                ),
+        );
+      },
+    );
+  }
+
+  Widget _statPill(String label, int count) {
+    return Container(
+      padding: const EdgeInsets.symmetric(vertical: 14, horizontal: 16),
+      decoration: BoxDecoration(
+        color: AppPalette.paper,
+        borderRadius: BorderRadius.circular(28),
+        border: Border.all(color: AppPalette.sage),
+      ),
+      child: Column(
+        children: [
+          Text(label, style: TextStyle(fontSize: 12, color: Colors.grey[600])),
+          const SizedBox(height: 4),
+          Text(
+            '$count일',
+            style: const TextStyle(
+              fontSize: 18,
+              fontWeight: FontWeight.bold,
+              color: AppPalette.ink,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _legendDot(Color color, String label) {
+    return Row(
+      children: [
+        Container(
+          width: 12,
+          height: 12,
+          decoration: BoxDecoration(color: color, shape: BoxShape.circle),
+        ),
+        const SizedBox(width: 6),
+        Text(label, style: TextStyle(fontSize: 12, color: Colors.grey[600])),
+      ],
+    );
+  }
+
+  Widget _legendIcon(IconData icon, Color color, String label) {
+    return Row(
+      children: [
+        Icon(icon, size: 14, color: color),
+        const SizedBox(width: 6),
+        Text(label, style: TextStyle(fontSize: 12, color: Colors.grey[600])),
+      ],
+    );
+  }
+}