diff --git a/TodoFlow/Package.swift b/TodoFlow/Package.swift
new file mode 100644
index 0000000..a469370
--- /dev/null
+++ b/TodoFlow/Package.swift
@@ -0,0 +1,13 @@
+// swift-tools-version: 5.9
+import PackageDescription
+
+let package = Package(
+    name: "TodoFlow",
+    platforms: [.macOS(.v13)],
+    targets: [
+        .executableTarget(
+            name: "TodoFlow",
+            path: "Sources/TodoFlow"
+        )
+    ]
+)
diff --git a/TodoFlow/Sources/TodoFlow/AppStore.swift b/TodoFlow/Sources/TodoFlow/AppStore.swift
new file mode 100644
index 0000000..521c0a8
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/AppStore.swift
@@ -0,0 +1,193 @@
+import Foundation
+import SwiftUI
+
+// MARK: - AppStore
+
+@MainActor
+final class AppStore: ObservableObject {
+
+    @Published var courses: [Course] = []
+    @Published var activities: [Activity] = []
+
+    // MARK: Init
+
+    init() {
+        load()
+    }
+
+    // MARK: - Persistence
+
+    private var saveURL: URL {
+        let dir = FileManager.default
+            .urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
+            .appendingPathComponent("TodoFlow", isDirectory: true)
+        try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        return dir.appendingPathComponent("data.json")
+    }
+
+    private struct Snapshot: Codable {
+        var courses: [Course]
+        var activities: [Activity]
+    }
+
+    func save() {
+        let snap = Snapshot(courses: courses, activities: activities)
+        if let data = try? JSONEncoder().encode(snap) {
+            try? data.write(to: saveURL, options: .atomic)
+        }
+    }
+
+    func load() {
+        guard
+            let data = try? Data(contentsOf: saveURL),
+            let snap = try? JSONDecoder().decode(Snapshot.self, from: data)
+        else {
+            insertSampleData()
+            return
+        }
+        courses    = snap.courses
+        activities = snap.activities
+    }
+
+    // MARK: - Course CRUD
+
+    func addCourse(_ c: Course)    { courses.append(c); save() }
+    func updateCourse(_ c: Course) { if let i = courses.firstIndex(where: { $0.id == c.id }) { courses[i] = c; save() } }
+    func deleteCourse(_ c: Course) { courses.removeAll { $0.id == c.id }; save() }
+
+    // MARK: - Assignment CRUD
+
+    func addAssignment(_ a: Assignment) {
+        guard let i = courses.firstIndex(where: { $0.id == a.courseId }) else { return }
+        courses[i].assignments.append(a)
+        save()
+    }
+
+    func toggleAssignment(_ a: Assignment) {
+        for i in courses.indices {
+            if let j = courses[i].assignments.firstIndex(where: { $0.id == a.id }) {
+                courses[i].assignments[j].isCompleted.toggle()
+                save()
+                return
+            }
+        }
+    }
+
+    func updateAssignment(_ a: Assignment) {
+        for i in courses.indices {
+            if let j = courses[i].assignments.firstIndex(where: { $0.id == a.id }) {
+                courses[i].assignments[j] = a
+                save()
+                return
+            }
+        }
+    }
+
+    func deleteAssignment(_ a: Assignment) {
+        for i in courses.indices { courses[i].assignments.removeAll { $0.id == a.id } }
+        save()
+    }
+
+    // MARK: - Activity CRUD
+
+    func addActivity(_ a: Activity)    { activities.append(a); save() }
+    func updateActivity(_ a: Activity) { if let i = activities.firstIndex(where: { $0.id == a.id }) { activities[i] = a; save() } }
+    func deleteActivity(_ a: Activity) { activities.removeAll { $0.id == a.id }; save() }
+
+    // MARK: - Sticky Note CRUD
+
+    func addStickyNote(_ note: StickyNote, to activityId: UUID) {
+        guard let i = activities.firstIndex(where: { $0.id == activityId }) else { return }
+        activities[i].stickyNotes.append(note)
+        save()
+    }
+
+    func updateStickyNote(_ note: StickyNote, in activityId: UUID) {
+        guard let i = activities.firstIndex(where: { $0.id == activityId }),
+              let j = activities[i].stickyNotes.firstIndex(where: { $0.id == note.id }) else { return }
+        activities[i].stickyNotes[j] = note
+        save()
+    }
+
+    func deleteStickyNote(_ noteId: UUID, from activityId: UUID) {
+        guard let i = activities.firstIndex(where: { $0.id == activityId }) else { return }
+        activities[i].stickyNotes.removeAll { $0.id == noteId }
+        save()
+    }
+
+    // MARK: - Calendar feed
+
+    var calendarEvents: [CalendarEvent] {
+        var events: [CalendarEvent] = []
+        for course in courses {
+            for a in course.assignments where !a.isCompleted {
+                events.append(CalendarEvent(
+                    title: a.title,
+                    date: a.dueDate,
+                    courseId: course.id,
+                    colorHex: course.colorHex
+                ))
+            }
+        }
+        for act in activities {
+            events.append(CalendarEvent(
+                title: act.title,
+                date: act.startDate,
+                courseId: nil,
+                colorHex: Activity.colorHex(for: act.category)
+            ))
+        }
+        return events.sorted { $0.date < $1.date }
+    }
+
+    var upcomingCount: Int {
+        let horizon = Calendar.current.date(byAdding: .day, value: 7, to: Date())!
+        return courses.reduce(0) { sum, c in
+            sum + c.assignments.filter { !$0.isCompleted && $0.dueDate >= Date() && $0.dueDate <= horizon }.count
+        }
+    }
+
+    // MARK: - Sample data
+
+    private func insertSampleData() {
+        let cal = Calendar.current
+        let now = Date()
+        func days(_ n: Int) -> Date { cal.date(byAdding: .day, value: n, to: now)! }
+
+        var cs = Course(name: "数据结构", code: "CS101", professor: "张教授", colorHex: "3B82F6")
+        cs.assignments = [
+            Assignment(title: "作业一：链表实现", dueDate: days(3),  courseId: cs.id),
+            Assignment(title: "期中项目提交",     dueDate: days(14), courseId: cs.id),
+        ]
+
+        var eng = Course(name: "学术英语写作", code: "ENG201", professor: "Smith 教授", colorHex: "10B981")
+        eng.assignments = [
+            Assignment(title: "Essay Draft 1", dueDate: days(5),  courseId: eng.id),
+            Assignment(title: "Final Essay",   dueDate: days(21), courseId: eng.id),
+        ]
+
+        var econ = Course(name: "微观经济学", code: "ECON101", professor: "李教授", colorHex: "F59E0B")
+        econ.assignments = [
+            Assignment(title: "第三章习题集", dueDate: days(7), courseId: econ.id),
+        ]
+
+        courses = [cs, eng, econ]
+
+        activities = [
+            Activity(
+                title: "学生会策划会议",
+                startDate: days(2),
+                description: "讨论五四晚会安排",
+                category: "会议"
+            ),
+            Activity(
+                title: "NLP 科研训练项目",
+                startDate: days(-7),
+                endDate: days(60),
+                description: "基于大模型的情感分析研究",
+                category: "研究"
+            ),
+        ]
+        save()
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Models.swift b/TodoFlow/Sources/TodoFlow/Models.swift
new file mode 100644
index 0000000..ec351db
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Models.swift
@@ -0,0 +1,140 @@
+import Foundation
+
+// MARK: - Course
+
+struct Course: Identifiable, Codable, Hashable {
+    var id: UUID = UUID()
+    var name: String
+    var code: String
+    var professor: String
+    var colorHex: String
+    var folderPath: String?          // override; default = ~/Desktop/<name>
+    var eLearningCourseId: Int?      // Moodle course ID
+    var assignments: [Assignment] = []
+    var createdAt: Date = Date()
+}
+
+// MARK: - Assignment
+
+struct Assignment: Identifiable, Codable, Hashable {
+    var id: UUID = UUID()
+    var title: String
+    var dueDate: Date
+    var courseId: UUID
+    var isCompleted: Bool = false
+    var notes: String = ""
+    var source: Source = .manual
+
+    enum Source: String, Codable {
+        case manual
+        case elearning
+    }
+}
+
+// MARK: - Activity
+
+struct Activity: Identifiable, Codable {
+    var id: UUID = UUID()
+    var title: String
+    var startDate: Date
+    var endDate: Date?
+    var description: String = ""
+    var category: String = "项目"   // free-form; was enum, kept as String for Codable compat
+    var stickyNotes: [StickyNote] = []
+    var createdAt: Date = Date()
+
+    // Default suggestions shown in the add sheet
+    static let suggestedCategories = ["项目", "会议", "活动", "研究", "比赛", "实习", "社团", "其他"]
+
+    static func icon(for category: String) -> String {
+        switch category {
+        case "项目":  return "target"
+        case "会议":  return "person.2"
+        case "活动":  return "calendar.badge.plus"
+        case "研究":  return "magnifyingglass"
+        case "比赛":  return "trophy"
+        case "实习":  return "briefcase"
+        case "社团":  return "person.3"
+        default:     return "star"
+        }
+    }
+
+    // Deterministic color per category name (same name → same color)
+    static func colorHex(for category: String) -> String {
+        let palette = ["3B82F6", "8B5CF6", "F59E0B", "10B981", "EF4444", "EC4899", "06B6D4", "84CC16"]
+        let hash = category.unicodeScalars.reduce(0) { $0 &+ Int($1.value) }
+        return palette[abs(hash) % palette.count]
+    }
+}
+
+// MARK: - StickyNote
+
+struct StickyNote: Identifiable, Codable {
+    var id: UUID = UUID()
+    var content: String
+    var colorName: StickyColor = .yellow
+    var createdAt: Date = Date()
+    var activityId: UUID
+
+    enum StickyColor: String, Codable, CaseIterable {
+        case yellow = "yellow"
+        case pink   = "pink"
+        case blue   = "blue"
+        case green  = "green"
+        case purple = "purple"
+    }
+}
+
+// MARK: - Local File (not Codable – rebuilt at runtime)
+
+struct LocalFile: Identifiable {
+    var id: String { path }
+    var name: String
+    var path: String
+    var category: FileCategory
+    var dateModified: Date
+    var fileExtension: String
+
+    enum FileCategory: String, CaseIterable {
+        case courseware = "课件"
+        case reading    = "阅读材料"
+        case lecture    = "讲解视频"
+        case submission = "作业提交"
+        case other      = "其他"
+    }
+}
+
+// MARK: - eLearning Resource
+
+struct ELearningResource: Identifiable, Codable {
+    var id: String
+    var courseId: Int
+    var courseName: String
+    var name: String
+    var modType: String    // assign / resource / url / folder / quiz …
+    var url: String
+    var addedTimestamp: Date
+    var isNew: Bool = false
+
+    var typeIcon: String {
+        switch modType {
+        case "resource": return "doc.fill"
+        case "url":      return "link"
+        case "assign":   return "pencil.and.list.clipboard"
+        case "forum":    return "bubble.left.and.bubble.right"
+        case "quiz":     return "questionmark.circle.fill"
+        case "folder":   return "folder.fill"
+        default:         return "doc"
+        }
+    }
+}
+
+// MARK: - Calendar Event (computed, not persisted)
+
+struct CalendarEvent: Identifiable {
+    var id: String { "\(title)-\(date.timeIntervalSince1970)-\(courseId?.uuidString ?? "act")" }
+    var title: String
+    var date: Date
+    var courseId: UUID?
+    var colorHex: String
+}
diff --git a/TodoFlow/Sources/TodoFlow/Services/ELearningService.swift b/TodoFlow/Sources/TodoFlow/Services/ELearningService.swift
new file mode 100644
index 0000000..e2c3117
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Services/ELearningService.swift
@@ -0,0 +1,289 @@
+import Foundation
+import Security
+
+// MARK: - ELearningService
+// Connects to Fudan elearning (Moodle) via the standard Moodle Mobile App web service.
+// Credentials are stored only in the macOS Keychain – never transmitted elsewhere.
+
+@MainActor
+final class ELearningService: ObservableObject {
+
+    @Published var isLoggedIn   = false
+    @Published var isLoading    = false
+    @Published var errorMessage: String?
+    @Published var enrolledCourses: [MoodleCourse] = []
+    @Published var resources: [ELearningResource] = []
+    @Published var lastSyncDate: Date?
+
+    private var wsToken: String?
+    private var currentUserId: Int?
+    private let base = "https://elearning.fudan.edu.cn"
+    private var syncTask: Task<Void, Never>?
+
+    // MARK: - Moodle types
+
+    struct MoodleCourse: Codable, Identifiable {
+        let id: Int
+        let fullname: String
+        let shortname: String
+    }
+
+    private struct TokenResponse: Codable {
+        let token: String?
+        let error: String?
+        let errorcode: String?
+    }
+
+    private struct SiteInfo: Codable {
+        let userid: Int
+        let username: String
+        let fullname: String?
+    }
+
+    private struct CourseModule: Codable {
+        let id: Int
+        let name: String
+        let modname: String
+        let url: String?
+        let timemodified: Int?
+    }
+
+    private struct Section: Codable {
+        let name: String
+        let modules: [CourseModule]
+    }
+
+    // MARK: - Session restore
+
+    func restoreSession() {
+        guard let token = Keychain.load("tf_elearning_token") else { return }
+        wsToken = token
+        if let uid = UserDefaults.standard.object(forKey: "tf_elearning_userid") as? Int {
+            currentUserId = uid
+        }
+        isLoggedIn = true
+        loadPersistedResources()
+    }
+
+    // MARK: - Login
+
+    func login(username: String, password: String) async -> Bool {
+        isLoading    = true
+        errorMessage = nil
+        defer { isLoading = false }
+
+        guard var components = URLComponents(string: "\(base)/login/token.php") else { return false }
+        components.queryItems = [
+            URLQueryItem(name: "username", value: username),
+            URLQueryItem(name: "password", value: password),
+            URLQueryItem(name: "service",  value: "moodle_mobile_app"),
+        ]
+
+        var req = URLRequest(url: components.url!)
+        req.httpMethod = "POST"
+        req.httpBody   = components.percentEncodedQuery?.data(using: .utf8)
+        req.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
+
+        do {
+            let (data, _) = try await URLSession.shared.data(for: req)
+            let resp = try JSONDecoder().decode(TokenResponse.self, from: data)
+
+            if let token = resp.token {
+                wsToken = token
+                Keychain.save("tf_elearning_token", value: token)
+                Keychain.save("tf_elearning_user",  value: username)
+                await fetchSiteInfo()
+                isLoggedIn = true
+                await fetchEnrolledCourses()
+                return true
+            } else {
+                errorMessage = resp.error ?? "登录失败，请检查账号密码"
+                return false
+            }
+        } catch {
+            errorMessage = "网络错误：\(error.localizedDescription)"
+            return false
+        }
+    }
+
+    func logout() {
+        wsToken       = nil
+        currentUserId = nil
+        isLoggedIn    = false
+        resources     = []
+        enrolledCourses = []
+        syncTask?.cancel()
+        Keychain.delete("tf_elearning_token")
+        Keychain.delete("tf_elearning_user")
+        UserDefaults.standard.removeObject(forKey: "tf_elearning_userid")
+        saveResources([])
+    }
+
+    // MARK: - Fetch
+
+    private func fetchSiteInfo() async {
+        guard let token = wsToken,
+              let data  = await call("core_webservice_get_site_info", params: [:], token: token),
+              let info  = try? JSONDecoder().decode(SiteInfo.self, from: data) else { return }
+        currentUserId = info.userid
+        UserDefaults.standard.set(info.userid, forKey: "tf_elearning_userid")
+    }
+
+    func fetchEnrolledCourses() async {
+        guard let token = wsToken, let uid = currentUserId else { return }
+        guard let data = await call(
+            "core_enrol_get_users_courses",
+            params: ["userid": "\(uid)"],
+            token: token
+        ), let courses = try? JSONDecoder().decode([MoodleCourse].self, from: data) else { return }
+        enrolledCourses = courses
+    }
+
+    func syncResources(for courseId: Int) async -> [ELearningResource] {
+        guard let token = wsToken else { return [] }
+        guard let data = await call(
+            "core_course_get_contents",
+            params: ["courseid": "\(courseId)"],
+            token: token
+        ), let sections = try? JSONDecoder().decode([Section].self, from: data) else { return [] }
+
+        let courseName = enrolledCourses.first { $0.id == courseId }?.fullname ?? ""
+        var result: [ELearningResource] = []
+        for section in sections {
+            for mod in section.modules {
+                result.append(ELearningResource(
+                    id:               "\(courseId)_\(mod.id)",
+                    courseId:         courseId,
+                    courseName:       courseName,
+                    name:             mod.name,
+                    modType:          mod.modname,
+                    url:              mod.url ?? "",
+                    addedTimestamp:   mod.timemodified.map { Date(timeIntervalSince1970: TimeInterval($0)) } ?? Date()
+                ))
+            }
+        }
+        return result
+    }
+
+    func syncAll() async {
+        guard isLoggedIn else { return }
+        isLoading = true
+        defer { isLoading = false }
+
+        await fetchEnrolledCourses()
+
+        let oldIds = Set(resources.map(\.id))
+        var fresh: [ELearningResource] = []
+        for course in enrolledCourses {
+            var batch = await syncResources(for: course.id)
+            for i in batch.indices {
+                batch[i].isNew = !oldIds.contains(batch[i].id)
+            }
+            fresh.append(contentsOf: batch)
+        }
+        resources    = fresh
+        lastSyncDate = Date()
+        saveResources(fresh)
+    }
+
+    // Mark a resource as "seen" (removes the "new" badge)
+    func markSeen(_ resourceId: String) {
+        if let i = resources.firstIndex(where: { $0.id == resourceId }) {
+            resources[i].isNew = false
+            saveResources(resources)
+        }
+    }
+
+    // MARK: - Auto-sync
+
+    func startAutoSync(intervalMinutes: Int) {
+        syncTask?.cancel()
+        guard intervalMinutes > 0 else { return }
+        syncTask = Task { [weak self] in
+            while !Task.isCancelled {
+                try? await Task.sleep(nanoseconds: UInt64(intervalMinutes) * 60 * 1_000_000_000)
+                guard !Task.isCancelled else { break }
+                await self?.syncAll()
+            }
+        }
+    }
+
+    // MARK: - Persistence (eLearning resources survive restarts)
+
+    private var resourcesURL: URL {
+        let dir = FileManager.default
+            .urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
+            .appendingPathComponent("TodoFlow", isDirectory: true)
+        try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        return dir.appendingPathComponent("elearning.json")
+    }
+
+    private func saveResources(_ r: [ELearningResource]) {
+        if let data = try? JSONEncoder().encode(r) {
+            try? data.write(to: resourcesURL, options: .atomic)
+        }
+    }
+
+    private func loadPersistedResources() {
+        guard let data = try? Data(contentsOf: resourcesURL),
+              let r    = try? JSONDecoder().decode([ELearningResource].self, from: data) else { return }
+        // Clear "new" flags on restart – only mark new after an actual sync
+        resources = r.map { var x = $0; x.isNew = false; return x }
+    }
+
+    // MARK: - Moodle REST helper
+
+    private func call(_ function: String, params: [String: String], token: String) async -> Data? {
+        var components = URLComponents(string: "\(base)/webservice/rest/server.php")!
+        var items: [URLQueryItem] = [
+            URLQueryItem(name: "wstoken",             value: token),
+            URLQueryItem(name: "wsfunction",          value: function),
+            URLQueryItem(name: "moodlewsrestformat",  value: "json"),
+        ]
+        for (k, v) in params { items.append(URLQueryItem(name: k, value: v)) }
+        components.queryItems = items
+        guard let url = components.url else { return nil }
+        return try? await URLSession.shared.data(from: url).0
+    }
+}
+
+// MARK: - Keychain helper
+
+enum Keychain {
+    private static let service = "TodoFlow"
+
+    static func save(_ key: String, value: String) {
+        let data = Data(value.utf8)
+        let q: [String: Any] = [
+            kSecClass as String:       kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
+            kSecValueData as String:   data,
+        ]
+        SecItemDelete(q as CFDictionary)
+        SecItemAdd(q as CFDictionary, nil)
+    }
+
+    static func load(_ key: String) -> String? {
+        let q: [String: Any] = [
+            kSecClass as String:       kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
+            kSecReturnData as String:  true,
+            kSecMatchLimit as String:  kSecMatchLimitOne,
+        ]
+        var result: AnyObject?
+        SecItemCopyMatching(q as CFDictionary, &result)
+        guard let data = result as? Data else { return nil }
+        return String(data: data, encoding: .utf8)
+    }
+
+    static func delete(_ key: String) {
+        let q: [String: Any] = [
+            kSecClass as String:       kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
+        ]
+        SecItemDelete(q as CFDictionary)
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Services/FileService.swift b/TodoFlow/Sources/TodoFlow/Services/FileService.swift
new file mode 100644
index 0000000..83ed0cc
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Services/FileService.swift
@@ -0,0 +1,140 @@
+import Foundation
+import AppKit
+
+// MARK: - FileService
+// Scans a local folder and auto-categorises files by name / extension.
+
+enum FileService {
+
+    // MARK: - Public API
+
+    static func defaultFolderPath(for courseName: String) -> String {
+        let desktop = FileManager.default
+            .urls(for: .desktopDirectory, in: .userDomainMask)[0]
+        return desktop.appendingPathComponent(courseName).path
+    }
+
+    static func folderExists(at path: String) -> Bool {
+        var isDir: ObjCBool = false
+        let exists = FileManager.default.fileExists(atPath: path, isDirectory: &isDir)
+        return exists && isDir.boolValue
+    }
+
+    static func files(at path: String) -> [LocalFile] {
+        let url = URL(fileURLWithPath: path)
+        guard let contents = try? FileManager.default.contentsOfDirectory(
+            at: url,
+            includingPropertiesForKeys: [.contentModificationDateKey, .isRegularFileKey],
+            options: [.skipsHiddenFiles]
+        ) else { return [] }
+
+        return contents.compactMap { fileURL -> LocalFile? in
+            guard
+                let res = try? fileURL.resourceValues(forKeys: [.contentModificationDateKey, .isRegularFileKey]),
+                res.isRegularFile == true
+            else { return nil }
+
+            let name  = fileURL.lastPathComponent
+            let ext   = fileURL.pathExtension.lowercased()
+            let mDate = res.contentModificationDate ?? Date()
+
+            return LocalFile(
+                name:         name,
+                path:         fileURL.path,
+                category:     categorise(name: name, ext: ext),
+                dateModified: mDate,
+                fileExtension: ext
+            )
+        }
+        .sorted { $0.dateModified > $1.dateModified }
+    }
+
+    static func open(_ file: LocalFile) {
+        NSWorkspace.shared.open(URL(fileURLWithPath: file.path))
+    }
+
+    static func openFolder(at path: String) {
+        NSWorkspace.shared.open(URL(fileURLWithPath: path))
+    }
+
+    // MARK: - Icons
+
+    static func fileIcon(_ ext: String) -> String {
+        switch ext {
+        case "pdf":              return "doc.richtext"
+        case "ppt", "pptx":     return "rectangle.on.rectangle"
+        case "doc", "docx":     return "doc.text"
+        case "xls", "xlsx":     return "tablecells"
+        case "mp4", "mov", "avi", "mkv": return "play.rectangle.fill"
+        case "zip", "rar", "7z": return "archivebox"
+        case "png", "jpg", "jpeg", "heic": return "photo"
+        case "key":              return "rectangle.on.rectangle.angled"
+        case "pages":            return "doc.text.fill"
+        default:                 return "doc"
+        }
+    }
+
+    static func categoryIcon(_ cat: LocalFile.FileCategory) -> String {
+        switch cat {
+        case .courseware:  return "rectangle.on.rectangle"
+        case .reading:     return "book"
+        case .lecture:     return "play.rectangle"
+        case .submission:  return "paperclip"
+        case .other:       return "doc"
+        }
+    }
+
+    static func categoryColor(_ cat: LocalFile.FileCategory) -> String {
+        switch cat {
+        case .courseware:  return "3B82F6"   // blue
+        case .reading:     return "8B5CF6"   // violet
+        case .lecture:     return "EC4899"   // pink
+        case .submission:  return "F59E0B"   // amber
+        case .other:       return "6B7280"   // gray
+        }
+    }
+
+    // MARK: - Categorisation logic
+
+    private static func categorise(name: String, ext: String) -> LocalFile.FileCategory {
+        let lower = name.lowercased()
+
+        // Video → lecture recording
+        if ["mp4", "mov", "avi", "mkv", "m4v", "wmv"].contains(ext) {
+            return .lecture
+        }
+
+        // Submission keywords
+        if lower.contains("submit") || lower.contains("作业") ||
+           lower.contains("hw") || lower.contains("homework") ||
+           lower.contains("assignment") || lower.contains("submission") {
+            return .submission
+        }
+
+        // Slides / Courseware keywords
+        if lower.contains("slide") || lower.contains("lec") ||
+           lower.contains("week") || lower.contains("chapter") ||
+           lower.contains("课件") || lower.contains("讲义") ||
+           ext == "pptx" || ext == "ppt" || ext == "key" {
+            return .courseware
+        }
+
+        // Reading material keywords
+        if lower.contains("reading") || lower.contains("paper") ||
+           lower.contains("article") || lower.contains("阅读") ||
+           lower.contains("文献") || lower.contains("论文") {
+            return .reading
+        }
+
+        // PDF: courseware if slide-like name, else reading
+        if ext == "pdf" {
+            if lower.contains("lec") || lower.contains("slide") ||
+               lower.contains("课件") || lower.contains("week") {
+                return .courseware
+            }
+            return .reading
+        }
+
+        return .other
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Theme.swift b/TodoFlow/Sources/TodoFlow/Theme.swift
new file mode 100644
index 0000000..52478d8
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Theme.swift
@@ -0,0 +1,118 @@
+import SwiftUI
+
+// MARK: - Color from hex
+
+extension Color {
+    init(hex: String) {
+        let h = hex.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
+        var int: UInt64 = 0
+        Scanner(string: h).scanHexInt64(&int)
+        let a, r, g, b: UInt64
+        switch h.count {
+        case 3:  (a,r,g,b) = (255,(int>>8)*17,(int>>4 & 0xF)*17,(int & 0xF)*17)
+        case 6:  (a,r,g,b) = (255,int>>16,int>>8 & 0xFF,int & 0xFF)
+        case 8:  (a,r,g,b) = (int>>24,int>>16 & 0xFF,int>>8 & 0xFF,int & 0xFF)
+        default: (a,r,g,b) = (255,0,0,0)
+        }
+        self.init(.sRGB,
+                  red:     Double(r)/255,
+                  green:   Double(g)/255,
+                  blue:    Double(b)/255,
+                  opacity: Double(a)/255)
+    }
+}
+
+// MARK: - Theme
+
+enum Theme {
+
+    // Backgrounds – warm off-white like Claude's UI
+    static let background   = Color(hex: "F7F6F3")
+    static let sidebarBg    = Color(hex: "EFEDE8")
+    static let cardBg       = Color.white
+    static let inputBg      = Color(hex: "F0EDE8")
+    static let divider      = Color(hex: "E5E2DC")
+
+    // Text
+    static let textPrimary   = Color(hex: "1A1A1A")
+    static let textSecondary = Color(hex: "6B6B6B")
+    static let textTertiary  = Color(hex: "9B9B9B")
+
+    // Accent – Claude amber
+    static let accent      = Color(hex: "D97706")
+    static let accentLight = Color(hex: "FEF3C7")
+
+    // Status
+    static let success = Color(hex: "059669")
+    static let warning = Color(hex: "D97706")
+    static let danger  = Color(hex: "DC2626")
+
+    // Sticky notes
+    static let stickyYellow = Color(hex: "FEF08A")
+    static let stickyPink   = Color(hex: "FBCFE8")
+    static let stickyBlue   = Color(hex: "BAE6FD")
+    static let stickyGreen  = Color(hex: "BBF7D0")
+    static let stickyPurple = Color(hex: "E9D5FF")
+
+    // Typography — Chinese: Songti SC (宋体简), English: Times New Roman
+    static let titleFont    = Font.custom("Songti SC", size: 24).weight(.semibold)
+    static let headlineFont = Font.custom("Songti SC", size: 16).weight(.semibold)
+    static let bodyFont     = Font.custom("Songti SC", size: 14)
+    static let captionFont  = Font.custom("Songti SC", size: 12)
+    static let smallFont    = Font.custom("Songti SC", size: 11).weight(.medium)
+
+    // English-specific typography (course codes, professor names, etc.)
+    static let englishBodyFont    = Font.custom("Times New Roman", size: 14)
+    static let englishHeadFont    = Font.custom("Times New Roman", size: 16)
+
+    // Layout
+    static let cornerRadius: CGFloat = 12
+    static let cardPadding:  CGFloat = 16
+    static let sectionSpacing: CGFloat = 24
+
+    // Sticky color helper
+    static func stickyColor(_ name: StickyNote.StickyColor) -> Color {
+        switch name {
+        case .yellow: return stickyYellow
+        case .pink:   return stickyPink
+        case .blue:   return stickyBlue
+        case .green:  return stickyGreen
+        case .purple: return stickyPurple
+        }
+    }
+
+    // Urgency color for due dates
+    static func urgencyColor(daysUntil: Int) -> Color {
+        if daysUntil < 0  { return danger }
+        if daysUntil <= 1 { return danger }
+        if daysUntil <= 3 { return warning }
+        return success
+    }
+}
+
+// MARK: - View Modifiers
+
+struct CardStyle: ViewModifier {
+    func body(content: Content) -> some View {
+        content
+            .background(Theme.cardBg)
+            .cornerRadius(Theme.cornerRadius)
+            .shadow(color: .black.opacity(0.055), radius: 8, x: 0, y: 2)
+    }
+}
+
+struct SectionHeaderStyle: ViewModifier {
+    func body(content: Content) -> some View {
+        content
+            .font(Theme.captionFont)
+            .fontWeight(.semibold)
+            .foregroundColor(Theme.textTertiary)
+            .textCase(.uppercase)
+            .tracking(0.5)
+    }
+}
+
+extension View {
+    func cardStyle() -> some View { modifier(CardStyle()) }
+    func sectionHeader() -> some View { modifier(SectionHeaderStyle()) }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/ActivitiesView.swift b/TodoFlow/Sources/TodoFlow/Views/ActivitiesView.swift
new file mode 100644
index 0000000..fa33b96
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/ActivitiesView.swift
@@ -0,0 +1,306 @@
+import SwiftUI
+
+// MARK: - ActivitiesView
+
+struct ActivitiesView: View {
+    @EnvironmentObject var store: AppStore
+
+    @State private var showAddActivity = false
+
+    private let columns = [GridItem(.flexible(), spacing: 16), GridItem(.flexible(), spacing: 16)]
+
+    // Unique categories present in data, preserving insertion order
+    private var categories: [String] {
+        var seen = Set<String>()
+        return store.activities.compactMap { seen.insert($0.category).inserted ? $0.category : nil }
+    }
+
+    var body: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: Theme.sectionSpacing) {
+
+                // ── Header ──────────────────────────────────────
+                HStack(alignment: .firstTextBaseline) {
+                    VStack(alignment: .leading, spacing: 2) {
+                        Text("活动 & 项目")
+                            .font(Theme.titleFont).foregroundColor(Theme.textPrimary)
+                        Text("\(store.activities.count) 项进行中")
+                            .font(Theme.bodyFont).foregroundColor(Theme.textSecondary)
+                    }
+                    Spacer()
+                    Button { showAddActivity = true } label: {
+                        Label("添加", systemImage: "plus")
+                            .font(.system(size: 13, weight: .medium))
+                    }
+                    .buttonStyle(.borderedProminent).tint(Theme.accent)
+                }
+                .padding(.horizontal, 24).padding(.top, 24)
+
+                if store.activities.isEmpty {
+                    EmptyPlaceholder(icon: "target", title: "还没有活动或项目", subtitle: "点击「添加」创建你的第一个项目")
+                } else {
+                    ForEach(categories, id: \.self) { cat in
+                        let items = store.activities.filter { $0.category == cat }
+                        if !items.isEmpty {
+                            VStack(alignment: .leading, spacing: 12) {
+                                HStack(spacing: 6) {
+                                    Image(systemName: Activity.icon(for: cat))
+                                        .font(.system(size: 11, weight: .semibold))
+                                        .foregroundColor(Color(hex: Activity.colorHex(for: cat)))
+                                    Text(cat)
+                                        .sectionHeader()
+                                }
+                                .padding(.horizontal, 24)
+
+                                LazyVGrid(columns: columns, spacing: 16) {
+                                    ForEach(items) { activity in
+                                        NavigationLink {
+                                            ActivityDetailView(activity: activity)
+                                                .environmentObject(store)
+                                        } label: {
+                                            ActivityCard(activity: activity)
+                                        }
+                                        .buttonStyle(.plain)
+                                    }
+                                }
+                                .padding(.horizontal, 24)
+                            }
+                        }
+                    }
+                }
+
+                Spacer(minLength: 40)
+            }
+        }
+        .background(Theme.background)
+        .sheet(isPresented: $showAddActivity) {
+            AddActivitySheet().environmentObject(store)
+        }
+    }
+}
+
+// MARK: - ActivityCard
+
+struct ActivityCard: View {
+    let activity: Activity
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            HStack {
+                Label(activity.category, systemImage: Activity.icon(for: activity.category))
+                    .font(Theme.captionFont).fontWeight(.semibold)
+                    .foregroundColor(Color(hex: Activity.colorHex(for: activity.category)))
+                    .padding(.horizontal, 8).padding(.vertical, 3)
+                    .background(Color(hex: Activity.colorHex(for: activity.category)).opacity(0.1))
+                    .cornerRadius(5)
+                Spacer()
+                if !activity.stickyNotes.isEmpty {
+                    HStack(spacing: 3) {
+                        Image(systemName: "note.text").font(.system(size: 10))
+                        Text("\(activity.stickyNotes.count)").font(.system(size: 10))
+                    }
+                    .foregroundColor(Theme.textTertiary)
+                }
+            }
+
+            Text(activity.title)
+                .font(Font.custom("Songti SC", size: 15).weight(.semibold))
+                .foregroundColor(Theme.textPrimary)
+                .lineLimit(2)
+
+            if !activity.description.isEmpty {
+                Text(activity.description)
+                    .font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    .lineLimit(2)
+            }
+
+            HStack(spacing: 6) {
+                Image(systemName: "calendar").font(.system(size: 10)).foregroundColor(Theme.textTertiary)
+                Text(activity.startDate, style: .date).font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+                if let end = activity.endDate {
+                    Text("→").font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+                    Text(end, style: .date).font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+                }
+                Spacer()
+            }
+
+            if let note = activity.stickyNotes.first {
+                Text(note.content)
+                    .font(Theme.captionFont).foregroundColor(Theme.textPrimary)
+                    .lineLimit(2)
+                    .padding(8)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .background(Theme.stickyColor(note.colorName))
+                    .cornerRadius(6)
+            }
+        }
+        .padding(Theme.cardPadding)
+        .cardStyle()
+    }
+}
+
+// MARK: - ActivityDetailView  (full page)
+
+struct ActivityDetailView: View {
+    @EnvironmentObject var store: AppStore
+
+    let activity: Activity
+
+    @State private var showAddNote = false
+
+    private var live: Activity { store.activities.first { $0.id == activity.id } ?? activity }
+
+    private let noteColumns = [
+        GridItem(.flexible(), spacing: 12),
+        GridItem(.flexible(), spacing: 12),
+        GridItem(.flexible(), spacing: 12),
+    ]
+
+    var body: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 0) {
+
+                // ── Header ─────────────────────────────────────
+                VStack(alignment: .leading, spacing: 6) {
+                    Label(live.category, systemImage: Activity.icon(for: live.category))
+                        .font(Theme.captionFont).fontWeight(.semibold)
+                        .foregroundColor(Color(hex: Activity.colorHex(for: live.category)))
+                        .padding(.horizontal, 8).padding(.vertical, 3)
+                        .background(Color(hex: Activity.colorHex(for: live.category)).opacity(0.1))
+                        .cornerRadius(5)
+
+                    Text(live.title)
+                        .font(Theme.titleFont).foregroundColor(Theme.textPrimary)
+
+                    HStack(spacing: 6) {
+                        Image(systemName: "calendar").font(.system(size: 12)).foregroundColor(Theme.textTertiary)
+                        Text(live.startDate, style: .date).font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                        if let end = live.endDate {
+                            Text("→").foregroundColor(Theme.textTertiary)
+                            Text(end, style: .date).font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                        }
+                    }
+
+                    if !live.description.isEmpty {
+                        Text(live.description)
+                            .font(Theme.bodyFont).foregroundColor(Theme.textSecondary)
+                            .padding(.top, 2)
+                    }
+                }
+                .padding(24)
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .background(Color(hex: Activity.colorHex(for: live.category)).opacity(0.05))
+
+                // ── 便利贴 ─────────────────────────────────────
+                PageSectionHeader(title: "便利贴", icon: "note.text")
+
+                VStack(alignment: .leading, spacing: 16) {
+                    HStack {
+                        Text("共 \(live.stickyNotes.count) 张")
+                            .font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                        Spacer()
+                        Button { showAddNote = true } label: {
+                            Label("添加便利贴", systemImage: "plus")
+                                .font(.system(size: 13, weight: .medium))
+                        }
+                        .buttonStyle(.borderedProminent).tint(Theme.accent)
+                    }
+                    .padding(.horizontal, 24).padding(.top, 12)
+
+                    if live.stickyNotes.isEmpty {
+                        EmptyPlaceholder(icon: "note.text", title: "还没有便利贴", subtitle: "添加想法、会议记录或备忘")
+                    } else {
+                        LazyVGrid(columns: noteColumns, spacing: 12) {
+                            ForEach(live.stickyNotes) { note in
+                                StickyNoteCard(note: note, activityId: live.id)
+                            }
+                        }
+                        .padding(.horizontal, 24)
+                    }
+
+                    Spacer(minLength: 60)
+                }
+            }
+        }
+        .background(Theme.background)
+        .navigationTitle(live.title)
+        .sheet(isPresented: $showAddNote) {
+            AddStickyNoteSheet(activityId: live.id).environmentObject(store)
+        }
+    }
+}
+
+// MARK: - StickyNoteCard
+
+struct StickyNoteCard: View {
+    let note: StickyNote
+    let activityId: UUID
+    @EnvironmentObject var store: AppStore
+
+    @State private var isEditing = false
+    @State private var editedContent = ""
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            HStack {
+                HStack(spacing: 4) {
+                    ForEach(StickyNote.StickyColor.allCases, id: \.self) { c in
+                        Circle()
+                            .fill(Theme.stickyColor(c))
+                            .frame(width: 10, height: 10)
+                            .overlay(
+                                Circle().stroke(c == note.colorName ? Color.gray.opacity(0.5) : Color.clear, lineWidth: 1.5)
+                            )
+                            .onTapGesture {
+                                var updated = note; updated.colorName = c
+                                store.updateStickyNote(updated, in: activityId)
+                            }
+                    }
+                }
+                Spacer()
+                Button { store.deleteStickyNote(note.id, from: activityId) } label: {
+                    Image(systemName: "xmark")
+                        .font(.system(size: 10))
+                        .foregroundColor(.gray.opacity(0.5))
+                }
+                .buttonStyle(.plain)
+            }
+
+            if isEditing {
+                TextEditor(text: $editedContent)
+                    .font(.system(size: 13))
+                    .frame(minHeight: 70)
+                    .scrollContentBackground(.hidden)
+                    .background(Color.clear)
+                HStack {
+                    Spacer()
+                    Button("保存") {
+                        var updated = note; updated.content = editedContent
+                        store.updateStickyNote(updated, in: activityId)
+                        isEditing = false
+                    }
+                    .font(.system(size: 11, weight: .semibold))
+                    .buttonStyle(.plain)
+                    .foregroundColor(Theme.accent)
+                }
+            } else {
+                Text(note.content)
+                    .font(.system(size: 13))
+                    .foregroundColor(Theme.textPrimary)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .onTapGesture { editedContent = note.content; isEditing = true }
+            }
+
+            Spacer()
+
+            Text(note.createdAt, style: .date)
+                .font(.system(size: 10))
+                .foregroundColor(.gray.opacity(0.5))
+        }
+        .padding(12)
+        .frame(minHeight: 120)
+        .background(Theme.stickyColor(note.colorName))
+        .cornerRadius(8)
+        .shadow(color: .black.opacity(0.07), radius: 4, x: 0, y: 2)
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/CalendarView.swift b/TodoFlow/Sources/TodoFlow/Views/CalendarView.swift
new file mode 100644
index 0000000..c30f81e
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/CalendarView.swift
@@ -0,0 +1,272 @@
+import SwiftUI
+
+// MARK: - CalendarView
+
+struct CalendarView: View {
+    @EnvironmentObject var store: AppStore
+
+    @State private var displayMonth = Date()
+    @State private var selectedDate: Date?
+
+    private let cal      = Calendar.current
+    private let weekdays = ["日", "一", "二", "三", "四", "五", "六"]
+    private let columns  = Array(repeating: GridItem(.flexible(), spacing: 0), count: 7)
+
+    var body: some View {
+        ScrollView {
+            VStack(spacing: Theme.sectionSpacing) {
+
+                // ── Header ─────────────────────────────────────
+                HStack(alignment: .firstTextBaseline) {
+                    VStack(alignment: .leading, spacing: 2) {
+                        Text(displayMonth, formatter: monthYearFmt)
+                            .font(Theme.titleFont)
+                            .foregroundColor(Theme.textPrimary)
+                        Text(subtitleText)
+                            .font(Theme.bodyFont)
+                            .foregroundColor(Theme.textSecondary)
+                    }
+                    Spacer()
+                    HStack(spacing: 6) {
+                        navButton("chevron.left") { shiftMonth(-1) }
+                        Button("今天") { displayMonth = Date(); selectedDate = Date() }
+                            .font(.system(size: 13, weight: .medium))
+                            .foregroundColor(Theme.accent)
+                            .buttonStyle(.plain)
+                        navButton("chevron.right") { shiftMonth(1) }
+                    }
+                }
+                .padding(.horizontal, 24)
+                .padding(.top, 24)
+
+                // ── Calendar grid ──────────────────────────────
+                VStack(spacing: 0) {
+                    // Weekday labels
+                    HStack(spacing: 0) {
+                        ForEach(weekdays, id: \.self) { d in
+                            Text(d)
+                                .font(Theme.captionFont)
+                                .fontWeight(.semibold)
+                                .foregroundColor(Theme.textTertiary)
+                                .frame(maxWidth: .infinity)
+                        }
+                    }
+                    .padding(.vertical, 10)
+                    .padding(.horizontal, 8)
+
+                    Divider().padding(.horizontal, 8)
+
+                    // Day cells
+                    LazyVGrid(columns: columns, spacing: 0) {
+                        ForEach(gridDays.indices, id: \.self) { idx in
+                            if let date = gridDays[idx] {
+                                DayCell(
+                                    date:           date,
+                                    events:         eventsOn(date),
+                                    isToday:        cal.isDateInToday(date),
+                                    isSelected:     selectedDate.map { cal.isDate($0, inSameDayAs: date) } ?? false,
+                                    isCurrentMonth: cal.isDate(date, equalTo: displayMonth, toGranularity: .month)
+                                )
+                                .onTapGesture { selectedDate = date }
+                            } else {
+                                Color.clear.frame(height: 68)
+                            }
+                        }
+                    }
+                    .padding(.horizontal, 4)
+                    .padding(.bottom, 4)
+                }
+                .cardStyle()
+                .padding(.horizontal, 24)
+
+                // ── Events for selected date ───────────────────
+                if let sel = selectedDate {
+                    let dayEvents = eventsOn(sel)
+                    if !dayEvents.isEmpty {
+                        VStack(alignment: .leading, spacing: 10) {
+                            Text(sel, formatter: dayFmt)
+                                .font(Theme.headlineFont)
+                                .foregroundColor(Theme.textPrimary)
+                                .padding(.horizontal, 24)
+
+                            ForEach(dayEvents) { ev in
+                                EventRow(event: ev).padding(.horizontal, 24)
+                            }
+                        }
+                    }
+                }
+
+                // ── Upcoming list ──────────────────────────────
+                VStack(alignment: .leading, spacing: 10) {
+                    Text("全部待办 (\(upcomingAll.count))")
+                        .font(Theme.headlineFont)
+                        .foregroundColor(Theme.textPrimary)
+                        .padding(.horizontal, 24)
+
+                    if upcomingAll.isEmpty {
+                        Text("暂无待办事项")
+                            .font(Theme.bodyFont)
+                            .foregroundColor(Theme.textTertiary)
+                            .padding(.horizontal, 24)
+                    } else {
+                        ForEach(upcomingAll.prefix(20)) { ev in
+                            EventRow(event: ev).padding(.horizontal, 24)
+                        }
+                    }
+                }
+
+                Spacer(minLength: 40)
+            }
+        }
+        .background(Theme.background)
+    }
+
+    // MARK: - Computed
+
+    private var subtitleText: String {
+        let n = store.upcomingCount
+        return n == 0 ? "本周无截止" : "本周 \(n) 项截止"
+    }
+
+    private var upcomingAll: [CalendarEvent] {
+        store.calendarEvents.filter { $0.date >= Date() }
+    }
+
+    private var gridDays: [Date?] {
+        guard let interval = cal.dateInterval(of: .month, for: displayMonth),
+              let firstWeekday = cal.dateComponents([.weekday], from: interval.start).weekday
+        else { return [] }
+
+        var days: [Date?] = Array(repeating: nil, count: firstWeekday - 1)
+        var cursor = interval.start
+        while cursor < interval.end {
+            days.append(cursor)
+            cursor = cal.date(byAdding: .day, value: 1, to: cursor)!
+        }
+        while days.count % 7 != 0 { days.append(nil) }
+        return days
+    }
+
+    private func eventsOn(_ date: Date) -> [CalendarEvent] {
+        store.calendarEvents.filter { cal.isDate($0.date, inSameDayAs: date) }
+    }
+
+    private func shiftMonth(_ delta: Int) {
+        displayMonth = cal.date(byAdding: .month, value: delta, to: displayMonth) ?? displayMonth
+    }
+
+    private func navButton(_ icon: String, action: @escaping () -> Void) -> some View {
+        Button(action: action) {
+            Image(systemName: icon)
+                .font(.system(size: 13, weight: .medium))
+                .foregroundColor(Theme.textSecondary)
+                .frame(width: 28, height: 28)
+                .background(Theme.inputBg)
+                .cornerRadius(6)
+        }
+        .buttonStyle(.plain)
+    }
+
+    // MARK: - Formatters
+
+    private var monthYearFmt: DateFormatter {
+        let f = DateFormatter(); f.dateFormat = "yyyy年 M月"; return f
+    }
+    private var dayFmt: DateFormatter {
+        let f = DateFormatter()
+        f.dateFormat = "M月d日 EEEE"
+        f.locale = Locale(identifier: "zh_CN")
+        return f
+    }
+}
+
+// MARK: - DayCell
+
+struct DayCell: View {
+    let date: Date
+    let events: [CalendarEvent]
+    let isToday: Bool
+    let isSelected: Bool
+    let isCurrentMonth: Bool
+
+    private let cal = Calendar.current
+
+    var body: some View {
+        VStack(spacing: 3) {
+            ZStack {
+                if isSelected {
+                    Circle().fill(Theme.accent).frame(width: 26, height: 26)
+                } else if isToday {
+                    Circle().fill(Theme.accent.opacity(0.15)).frame(width: 26, height: 26)
+                }
+                Text("\(cal.component(.day, from: date))")
+                    .font(.system(size: 12, weight: isToday || isSelected ? .semibold : .regular))
+                    .foregroundColor(
+                        isSelected       ? .white :
+                        isToday          ? Theme.accent :
+                        isCurrentMonth   ? Theme.textPrimary : Theme.textTertiary
+                    )
+            }
+
+            // Up to 3 event dots
+            HStack(spacing: 2) {
+                ForEach(events.prefix(3)) { ev in
+                    Circle()
+                        .fill(Color(hex: ev.colorHex))
+                        .frame(width: 4, height: 4)
+                }
+            }
+            .frame(height: 5)
+        }
+        .frame(maxWidth: .infinity)
+        .frame(height: 58)
+        .contentShape(Rectangle())
+    }
+}
+
+// MARK: - EventRow
+
+struct EventRow: View {
+    let event: CalendarEvent
+
+    private var daysUntil: Int {
+        Calendar.current.dateComponents([.day], from: .now, to: event.date).day ?? 0
+    }
+
+    private var daysLabel: String {
+        if daysUntil < 0  { return "已过期" }
+        if daysUntil == 0 { return "今天" }
+        return "\(daysUntil) 天后"
+    }
+
+    var body: some View {
+        HStack(spacing: 12) {
+            Rectangle()
+                .fill(Color(hex: event.colorHex))
+                .frame(width: 3)
+                .cornerRadius(2)
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text(event.title)
+                    .font(Theme.bodyFont)
+                    .foregroundColor(Theme.textPrimary)
+                    .lineLimit(1)
+                Text(event.date, style: .date)
+                    .font(Theme.captionFont)
+                    .foregroundColor(Theme.textSecondary)
+            }
+
+            Spacer()
+
+            Text(daysLabel)
+                .font(Theme.captionFont)
+                .foregroundColor(Theme.urgencyColor(daysUntil: daysUntil))
+                .padding(.horizontal, 9)
+                .padding(.vertical, 4)
+                .background(Theme.urgencyColor(daysUntil: daysUntil).opacity(0.1))
+                .cornerRadius(6)
+        }
+        .padding(12)
+        .cardStyle()
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/ContentView.swift b/TodoFlow/Sources/TodoFlow/Views/ContentView.swift
new file mode 100644
index 0000000..5231df7
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/ContentView.swift
@@ -0,0 +1,48 @@
+import SwiftUI
+
+// MARK: - Navigation tabs
+
+enum AppTab: String, CaseIterable, Hashable {
+    case calendar   = "日历"
+    case courses    = "课程"
+    case activities = "活动 & 项目"
+
+    var icon: String {
+        switch self {
+        case .calendar:   return "calendar"
+        case .courses:    return "books.vertical"
+        case .activities: return "target"
+        }
+    }
+}
+
+// MARK: - ContentView
+
+struct ContentView: View {
+    @EnvironmentObject var store: AppStore
+    @EnvironmentObject var eLearning: ELearningService
+
+    @State private var selectedTab: AppTab = .courses
+    @State private var showSettings = false
+
+    var body: some View {
+        NavigationSplitView(columnVisibility: .constant(.all)) {
+            SidebarView(selectedTab: $selectedTab, showSettings: $showSettings)
+                .navigationSplitViewColumnWidth(min: 200, ideal: 220, max: 260)
+        } detail: {
+            NavigationStack {
+                switch selectedTab {
+                case .calendar:   CalendarView()
+                case .courses:    CoursesView()
+                case .activities: ActivitiesView()
+                }
+            }
+        }
+        .navigationSplitViewStyle(.prominentDetail)
+        .sheet(isPresented: $showSettings) {
+            SettingsView()
+                .environmentObject(store)
+                .environmentObject(eLearning)
+        }
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/CourseDetailView.swift b/TodoFlow/Sources/TodoFlow/Views/CourseDetailView.swift
new file mode 100644
index 0000000..f252685
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/CourseDetailView.swift
@@ -0,0 +1,443 @@
+import SwiftUI
+
+// MARK: - CourseDetailView  (full-page, no tabs)
+
+struct CourseDetailView: View {
+    @EnvironmentObject var store: AppStore
+    @EnvironmentObject var eLearning: ELearningService
+
+    let course: Course
+
+    @State private var showAddAssignment = false
+    @State private var showEditCourse    = false
+
+    private var live: Course { store.courses.first { $0.id == course.id } ?? course }
+
+    var body: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 0) {
+
+                // ── Course header ──────────────────────────────
+                HStack(spacing: 0) {
+                    Rectangle()
+                        .fill(Color(hex: live.colorHex))
+                        .frame(width: 5)
+
+                    VStack(alignment: .leading, spacing: 6) {
+                        Text(live.code)
+                            .font(Theme.englishBodyFont)
+                            .fontWeight(.semibold)
+                            .foregroundColor(Color(hex: live.colorHex))
+                            .padding(.horizontal, 8).padding(.vertical, 3)
+                            .background(Color(hex: live.colorHex).opacity(0.1))
+                            .cornerRadius(5)
+                        Text(live.name)
+                            .font(Theme.titleFont)
+                            .foregroundColor(Theme.textPrimary)
+                        Text(live.professor)
+                            .font(Theme.englishBodyFont)
+                            .foregroundColor(Theme.textSecondary)
+                    }
+                    .padding(20)
+
+                    Spacer()
+                }
+                .background(Color(hex: live.colorHex).opacity(0.05))
+
+                // ── 作业 & DDL ─────────────────────────────────
+                PageSectionHeader(title: "作业 & DDL", icon: "checklist")
+                AssignmentsSection(course: live, showAddAssignment: $showAddAssignment)
+
+                // ── 本地文件 ───────────────────────────────────
+                PageSectionHeader(title: "本地文件", icon: "folder")
+                FilesSection(course: live)
+
+                // ── eLearning ──────────────────────────────────
+                PageSectionHeader(title: "eLearning", icon: "link")
+                ELearningSection(course: live)
+
+                Spacer(minLength: 60)
+            }
+        }
+        .background(Theme.background)
+        .navigationTitle(live.name)
+        .toolbar {
+            ToolbarItem(placement: .primaryAction) {
+                Button { showEditCourse = true } label: {
+                    Label("编辑课程", systemImage: "pencil")
+                }
+            }
+        }
+        .sheet(isPresented: $showAddAssignment) {
+            AddAssignmentSheet(courseId: live.id).environmentObject(store)
+        }
+        .sheet(isPresented: $showEditCourse) {
+            EditCourseSheet(course: live).environmentObject(store)
+        }
+    }
+}
+
+// MARK: - Page Section Header
+
+struct PageSectionHeader: View {
+    let title: String
+    let icon: String
+
+    var body: some View {
+        HStack(spacing: 10) {
+            Image(systemName: icon)
+                .font(.system(size: 15, weight: .semibold))
+                .foregroundColor(Theme.accent)
+            Text(title)
+                .font(Font.custom("Songti SC", size: 20).weight(.semibold))
+                .foregroundColor(Theme.textPrimary)
+            Spacer()
+        }
+        .padding(.horizontal, 24)
+        .padding(.top, 32)
+        .padding(.bottom, 2)
+
+        Rectangle()
+            .fill(Theme.divider)
+            .frame(height: 1.5)
+            .padding(.horizontal, 24)
+            .padding(.bottom, 8)
+    }
+}
+
+// MARK: - Assignments Section
+
+struct AssignmentsSection: View {
+    let course: Course
+    @Binding var showAddAssignment: Bool
+    @EnvironmentObject var store: AppStore
+
+    private var pending:   [Assignment] { course.assignments.filter { !$0.isCompleted }.sorted { $0.dueDate < $1.dueDate } }
+    private var completed: [Assignment] { course.assignments.filter {  $0.isCompleted }.sorted { $0.dueDate > $1.dueDate } }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 16) {
+            HStack {
+                Text("待完成 (\(pending.count))")
+                    .font(Theme.headlineFont).foregroundColor(Theme.textPrimary)
+                Spacer()
+                Button { showAddAssignment = true } label: {
+                    Label("添加", systemImage: "plus")
+                        .font(.system(size: 13, weight: .medium))
+                }
+                .buttonStyle(.borderedProminent).tint(Theme.accent)
+            }
+            .padding(.horizontal, 24).padding(.top, 12)
+
+            if pending.isEmpty {
+                EmptyPlaceholder(icon: "checkmark.circle", title: "没有待完成的作业", subtitle: "添加新作业或从 eLearning 同步")
+            } else {
+                VStack(spacing: 8) {
+                    ForEach(pending) { a in
+                        AssignmentRow(assignment: a).padding(.horizontal, 24)
+                    }
+                }
+            }
+
+            if !completed.isEmpty {
+                VStack(alignment: .leading, spacing: 8) {
+                    Text("已完成 (\(completed.count))")
+                        .sectionHeader()
+                        .padding(.horizontal, 24).padding(.top, 8)
+                    ForEach(completed) { a in
+                        AssignmentRow(assignment: a)
+                            .padding(.horizontal, 24)
+                            .opacity(0.5)
+                    }
+                }
+            }
+        }
+    }
+}
+
+// MARK: - AssignmentRow
+
+struct AssignmentRow: View {
+    let assignment: Assignment
+    @EnvironmentObject var store: AppStore
+
+    private var days: Int { Calendar.current.dateComponents([.day], from: .now, to: assignment.dueDate).day ?? 0 }
+
+    private var daysLabel: String {
+        if days < 0  { return "已过期" }
+        if days == 0 { return "今天截止" }
+        return "\(days) 天后"
+    }
+
+    var body: some View {
+        HStack(spacing: 12) {
+            Button { store.toggleAssignment(assignment) } label: {
+                Image(systemName: assignment.isCompleted ? "checkmark.circle.fill" : "circle")
+                    .font(.system(size: 18))
+                    .foregroundColor(assignment.isCompleted ? Theme.success : Theme.textTertiary)
+            }
+            .buttonStyle(.plain)
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text(assignment.title)
+                    .font(Theme.bodyFont).foregroundColor(Theme.textPrimary)
+                    .strikethrough(assignment.isCompleted)
+                    .lineLimit(1)
+                HStack(spacing: 8) {
+                    Text(assignment.dueDate, style: .date)
+                        .font(Theme.captionFont)
+                        .foregroundColor(Theme.urgencyColor(daysUntil: days))
+                    if assignment.source == .elearning {
+                        Label("eLearning", systemImage: "link")
+                            .font(.system(size: 10))
+                            .foregroundColor(Theme.textTertiary)
+                    }
+                }
+            }
+
+            Spacer()
+
+            Text(daysLabel)
+                .font(Theme.captionFont)
+                .foregroundColor(Theme.urgencyColor(daysUntil: days))
+                .padding(.horizontal, 8).padding(.vertical, 4)
+                .background(Theme.urgencyColor(daysUntil: days).opacity(0.1))
+                .cornerRadius(6)
+        }
+        .padding(12)
+        .cardStyle()
+        .contextMenu {
+            Button(role: .destructive) { store.deleteAssignment(assignment) } label: {
+                Label("删除", systemImage: "trash")
+            }
+        }
+    }
+}
+
+// MARK: - Files Section
+
+struct FilesSection: View {
+    let course: Course
+
+    @State private var files: [LocalFile] = []
+    @State private var selectedCategory: LocalFile.FileCategory?
+
+    private var folderPath: String {
+        course.folderPath ?? FileService.defaultFolderPath(for: course.name)
+    }
+
+    private var filtered: [LocalFile] {
+        guard let cat = selectedCategory else { return files }
+        return files.filter { $0.category == cat }
+    }
+
+    private var groups: [LocalFile.FileCategory: [LocalFile]] {
+        Dictionary(grouping: files, by: \.category)
+    }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 14) {
+            HStack {
+                VStack(alignment: .leading, spacing: 2) {
+                    Text(folderPath)
+                        .font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+                        .lineLimit(1).truncationMode(.middle)
+                }
+                Spacer()
+                Button("刷新") { files = FileService.files(at: folderPath) }
+                    .buttonStyle(.bordered)
+                Button("打开文件夹") { FileService.openFolder(at: folderPath) }
+                    .buttonStyle(.bordered)
+            }
+            .padding(.horizontal, 24).padding(.top, 12)
+
+            if !FileService.folderExists(at: folderPath) {
+                EmptyPlaceholder(
+                    icon: "folder.badge.questionmark",
+                    title: "未找到文件夹",
+                    subtitle: "请在桌面创建名为「\(course.name)」的文件夹"
+                )
+            } else if files.isEmpty {
+                EmptyPlaceholder(
+                    icon: "folder",
+                    title: "文件夹为空",
+                    subtitle: "将课程文件放入桌面「\(course.name)」文件夹"
+                )
+            } else {
+                ScrollView(.horizontal, showsIndicators: false) {
+                    HStack(spacing: 8) {
+                        FilterChip(label: "全部 (\(files.count))", isSelected: selectedCategory == nil)
+                            .onTapGesture { selectedCategory = nil }
+                        ForEach(LocalFile.FileCategory.allCases, id: \.self) { cat in
+                            if let count = groups[cat]?.count, count > 0 {
+                                FilterChip(
+                                    label: "\(cat.rawValue) (\(count))",
+                                    isSelected: selectedCategory == cat,
+                                    colorHex: FileService.categoryColor(cat)
+                                )
+                                .onTapGesture { selectedCategory = selectedCategory == cat ? nil : cat }
+                            }
+                        }
+                    }
+                    .padding(.horizontal, 24)
+                }
+
+                LazyVStack(spacing: 8) {
+                    ForEach(filtered) { file in
+                        FileRow(file: file).padding(.horizontal, 24)
+                    }
+                }
+            }
+        }
+        .onAppear { files = FileService.files(at: folderPath) }
+    }
+}
+
+struct FileRow: View {
+    let file: LocalFile
+
+    private var colorHex: String { FileService.categoryColor(file.category) }
+
+    var body: some View {
+        HStack(spacing: 12) {
+            Image(systemName: FileService.fileIcon(file.fileExtension))
+                .font(.system(size: 18))
+                .foregroundColor(Color(hex: colorHex))
+                .frame(width: 28)
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text(file.name)
+                    .font(Theme.bodyFont).foregroundColor(Theme.textPrimary).lineLimit(1)
+                Text(file.dateModified, style: .relative)
+                    .font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+            }
+            Spacer()
+            Text(file.category.rawValue)
+                .font(Theme.captionFont).foregroundColor(Color(hex: colorHex))
+                .padding(.horizontal, 8).padding(.vertical, 3)
+                .background(Color(hex: colorHex).opacity(0.1))
+                .cornerRadius(5)
+        }
+        .padding(12)
+        .cardStyle()
+        .contentShape(Rectangle())
+        .onTapGesture { FileService.open(file) }
+    }
+}
+
+struct FilterChip: View {
+    let label: String
+    let isSelected: Bool
+    var colorHex: String = "D97706"
+
+    var body: some View {
+        Text(label)
+            .font(Theme.captionFont)
+            .fontWeight(isSelected ? .semibold : .regular)
+            .foregroundColor(isSelected ? Color(hex: colorHex) : Theme.textSecondary)
+            .padding(.horizontal, 12).padding(.vertical, 6)
+            .background(isSelected ? Color(hex: colorHex).opacity(0.1) : Theme.inputBg)
+            .cornerRadius(20)
+    }
+}
+
+// MARK: - eLearning Section
+
+struct ELearningSection: View {
+    let course: Course
+    @EnvironmentObject var eLearning: ELearningService
+
+    private var courseResources: [ELearningResource] {
+        guard let cid = course.eLearningCourseId else { return [] }
+        return eLearning.resources.filter { $0.courseId == cid }
+    }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 14) {
+            HStack {
+                Spacer()
+                if eLearning.isLoading {
+                    ProgressView().scaleEffect(0.7)
+                } else if course.eLearningCourseId != nil {
+                    Button("同步") { Task { await eLearning.syncAll() } }
+                        .buttonStyle(.bordered)
+                }
+            }
+            .padding(.horizontal, 24).padding(.top, 12)
+
+            if !eLearning.isLoggedIn {
+                EmptyPlaceholder(icon: "lock", title: "未登录 eLearning", subtitle: "请在「设置」中登录 Fudan eLearning")
+            } else if course.eLearningCourseId == nil {
+                EmptyPlaceholder(
+                    icon: "link.badge.plus",
+                    title: "未关联 eLearning 课程",
+                    subtitle: "编辑课程，填写对应的 Moodle 课程 ID"
+                )
+            } else if courseResources.isEmpty {
+                EmptyPlaceholder(icon: "arrow.clockwise", title: "暂无内容", subtitle: "点击「同步」拉取最新内容")
+            } else {
+                let newItems = courseResources.filter(\.isNew)
+                if !newItems.isEmpty {
+                    VStack(alignment: .leading, spacing: 6) {
+                        Text("新增 (\(newItems.count))")
+                            .sectionHeader().padding(.horizontal, 24)
+                        ForEach(newItems) { r in
+                            ELearningRow(resource: r).padding(.horizontal, 24)
+                        }
+                    }
+                    .padding(.bottom, 4)
+                }
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("全部 (\(courseResources.count))")
+                        .sectionHeader().padding(.horizontal, 24)
+                    ForEach(courseResources) { r in
+                        ELearningRow(resource: r).padding(.horizontal, 24)
+                    }
+                }
+            }
+
+            Spacer(minLength: 40)
+        }
+    }
+}
+
+struct ELearningRow: View {
+    let resource: ELearningResource
+    @EnvironmentObject var eLearning: ELearningService
+
+    var body: some View {
+        HStack(spacing: 12) {
+            Image(systemName: resource.typeIcon)
+                .font(.system(size: 15))
+                .foregroundColor(Theme.accent)
+                .frame(width: 24)
+
+            VStack(alignment: .leading, spacing: 2) {
+                HStack(spacing: 6) {
+                    Text(resource.name)
+                        .font(Theme.bodyFont).foregroundColor(Theme.textPrimary).lineLimit(1)
+                    if resource.isNew {
+                        Text("新")
+                            .font(.system(size: 9, weight: .bold)).foregroundColor(.white)
+                            .padding(.horizontal, 5).padding(.vertical, 1)
+                            .background(Theme.danger).cornerRadius(3)
+                    }
+                }
+                Text(resource.addedTimestamp, style: .date)
+                    .font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+            }
+            Spacer()
+            Text(resource.modType)
+                .font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+        }
+        .padding(12)
+        .cardStyle()
+        .contentShape(Rectangle())
+        .onTapGesture {
+            if resource.isNew { eLearning.markSeen(resource.id) }
+            if let url = URL(string: resource.url), !resource.url.isEmpty {
+                NSWorkspace.shared.open(url)
+            }
+        }
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/CoursesView.swift b/TodoFlow/Sources/TodoFlow/Views/CoursesView.swift
new file mode 100644
index 0000000..7b0f9c7
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/CoursesView.swift
@@ -0,0 +1,228 @@
+import SwiftUI
+
+// MARK: - CoursesView
+
+struct CoursesView: View {
+    @EnvironmentObject var store: AppStore
+    @EnvironmentObject var eLearning: ELearningService
+
+    @State private var showAddCourse = false
+
+    private let columns = [
+        GridItem(.flexible(), spacing: 16),
+        GridItem(.flexible(), spacing: 16),
+        GridItem(.flexible(), spacing: 16),
+    ]
+
+    var body: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: Theme.sectionSpacing) {
+
+                // ── Header ─────────────────────────────────────
+                HStack(alignment: .firstTextBaseline) {
+                    VStack(alignment: .leading, spacing: 2) {
+                        Text("课程")
+                            .font(Theme.titleFont)
+                            .foregroundColor(Theme.textPrimary)
+                        Text("\(store.courses.count) 门课程 · \(totalPending) 项待完成")
+                            .font(Theme.bodyFont)
+                            .foregroundColor(Theme.textSecondary)
+                    }
+                    Spacer()
+                    Button { showAddCourse = true } label: {
+                        Label("添加课程", systemImage: "plus")
+                            .font(.system(size: 13, weight: .medium))
+                    }
+                    .buttonStyle(.borderedProminent)
+                    .tint(Theme.accent)
+                }
+                .padding(.horizontal, 24)
+                .padding(.top, 24)
+
+                // ── Course grid ────────────────────────────────
+                if store.courses.isEmpty {
+                    EmptyPlaceholder(
+                        icon: "books.vertical",
+                        title: "还没有课程",
+                        subtitle: "点击右上角「添加课程」开始"
+                    )
+                } else {
+                    LazyVGrid(columns: columns, spacing: 16) {
+                        ForEach(store.courses) { course in
+                            NavigationLink {
+                                CourseDetailView(course: course)
+                                    .environmentObject(store)
+                                    .environmentObject(eLearning)
+                            } label: {
+                                CourseCard(course: course)
+                            }
+                            .buttonStyle(.plain)
+                        }
+                    }
+                    .padding(.horizontal, 24)
+                }
+
+                Spacer(minLength: 40)
+            }
+        }
+        .background(Theme.background)
+        .sheet(isPresented: $showAddCourse) {
+            AddCourseSheet().environmentObject(store)
+        }
+    }
+
+    private var totalPending: Int {
+        store.courses.reduce(0) { $0 + $1.assignments.filter { !$0.isCompleted }.count }
+    }
+}
+
+// MARK: - CourseCard
+
+struct CourseCard: View {
+    let course: Course
+    @EnvironmentObject var store: AppStore
+
+    private var pending: Int { course.assignments.filter { !$0.isCompleted }.count }
+
+    private var nextDue: Assignment? {
+        course.assignments
+            .filter { !$0.isCompleted && $0.dueDate >= Date() }
+            .sorted { $0.dueDate < $1.dueDate }
+            .first
+    }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 0) {
+
+            // Colour accent bar
+            Rectangle()
+                .fill(Color(hex: course.colorHex))
+                .frame(height: 4)
+                .cornerRadius(Theme.cornerRadius, corners: [.topLeft, .topRight])
+
+            VStack(alignment: .leading, spacing: 8) {
+                HStack {
+                    Text(course.code)
+                        .font(Theme.englishBodyFont)
+                        .fontWeight(.semibold)
+                        .foregroundColor(Color(hex: course.colorHex))
+                        .padding(.horizontal, 8)
+                        .padding(.vertical, 3)
+                        .background(Color(hex: course.colorHex).opacity(0.12))
+                        .cornerRadius(5)
+                    Spacer()
+                }
+
+                Text(course.name)
+                    .font(.system(size: 15, weight: .semibold))
+                    .foregroundColor(Theme.textPrimary)
+                    .lineLimit(2)
+
+                Text(course.professor)
+                    .font(Theme.captionFont)
+                    .foregroundColor(Theme.textSecondary)
+            }
+            .padding(Theme.cardPadding)
+
+            Divider()
+
+            // Next deadline footer
+            Group {
+                if let next = nextDue {
+                    HStack(spacing: 6) {
+                        Image(systemName: "clock")
+                            .font(.system(size: 10))
+                            .foregroundColor(Theme.textTertiary)
+                        Text(next.title)
+                            .font(Theme.captionFont)
+                            .foregroundColor(Theme.textSecondary)
+                            .lineLimit(1)
+                        Spacer()
+                        Text(next.dueDate, style: .date)
+                            .font(.system(size: 10))
+                            .foregroundColor(Theme.textTertiary)
+                    }
+                } else {
+                    HStack(spacing: 6) {
+                        Image(systemName: "checkmark.circle")
+                            .font(.system(size: 10))
+                            .foregroundColor(Theme.success)
+                        Text("暂无待完成作业")
+                            .font(Theme.captionFont)
+                            .foregroundColor(Theme.textTertiary)
+                    }
+                }
+            }
+            .padding(.horizontal, Theme.cardPadding)
+            .padding(.vertical, 10)
+        }
+        .background(Theme.cardBg)
+        .cornerRadius(Theme.cornerRadius)
+        .shadow(color: .black.opacity(0.05), radius: 8, x: 0, y: 2)
+    }
+}
+
+// MARK: - Rounded corners helper
+
+extension View {
+    func cornerRadius(_ radius: CGFloat, corners: RectCorner) -> some View {
+        clipShape(RoundedCorners(radius: radius, corners: corners))
+    }
+}
+
+struct RectCorner: OptionSet {
+    let rawValue: Int
+    static let topLeft     = RectCorner(rawValue: 1 << 0)
+    static let topRight    = RectCorner(rawValue: 1 << 1)
+    static let bottomLeft  = RectCorner(rawValue: 1 << 2)
+    static let bottomRight = RectCorner(rawValue: 1 << 3)
+    static let all: RectCorner = [.topLeft, .topRight, .bottomLeft, .bottomRight]
+}
+
+struct RoundedCorners: Shape {
+    var radius: CGFloat
+    var corners: RectCorner
+    func path(in rect: CGRect) -> Path {
+        var path = Path()
+        let tl = corners.contains(.topLeft)
+        let tr = corners.contains(.topRight)
+        let bl = corners.contains(.bottomLeft)
+        let br = corners.contains(.bottomRight)
+        path.move(to: CGPoint(x: rect.minX + (tl ? radius : 0), y: rect.minY))
+        path.addLine(to: CGPoint(x: rect.maxX - (tr ? radius : 0), y: rect.minY))
+        if tr { path.addArc(center: CGPoint(x: rect.maxX - radius, y: rect.minY + radius), radius: radius, startAngle: .degrees(-90), endAngle: .degrees(0), clockwise: false) }
+        path.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY - (br ? radius : 0)))
+        if br { path.addArc(center: CGPoint(x: rect.maxX - radius, y: rect.maxY - radius), radius: radius, startAngle: .degrees(0), endAngle: .degrees(90), clockwise: false) }
+        path.addLine(to: CGPoint(x: rect.minX + (bl ? radius : 0), y: rect.maxY))
+        if bl { path.addArc(center: CGPoint(x: rect.minX + radius, y: rect.maxY - radius), radius: radius, startAngle: .degrees(90), endAngle: .degrees(180), clockwise: false) }
+        path.addLine(to: CGPoint(x: rect.minX, y: rect.minY + (tl ? radius : 0)))
+        if tl { path.addArc(center: CGPoint(x: rect.minX + radius, y: rect.minY + radius), radius: radius, startAngle: .degrees(180), endAngle: .degrees(270), clockwise: false) }
+        path.closeSubpath()
+        return path
+    }
+}
+
+// MARK: - Shared empty state
+
+struct EmptyPlaceholder: View {
+    let icon: String
+    let title: String
+    let subtitle: String
+
+    var body: some View {
+        VStack(spacing: 12) {
+            Image(systemName: icon)
+                .font(.system(size: 40))
+                .foregroundColor(Theme.textTertiary)
+            Text(title)
+                .font(Theme.headlineFont)
+                .foregroundColor(Theme.textSecondary)
+            Text(subtitle)
+                .font(Theme.captionFont)
+                .foregroundColor(Theme.textTertiary)
+                .multilineTextAlignment(.center)
+        }
+        .frame(maxWidth: .infinity)
+        .padding(60)
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/SettingsView.swift b/TodoFlow/Sources/TodoFlow/Views/SettingsView.swift
new file mode 100644
index 0000000..a746c51
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/SettingsView.swift
@@ -0,0 +1,154 @@
+import SwiftUI
+
+struct SettingsView: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+    @EnvironmentObject var eLearning: ELearningService
+
+    @State private var username    = ""
+    @State private var password    = ""
+    @State private var isLoggingIn = false
+    @State private var syncInterval = 30
+
+    var body: some View {
+        VStack(spacing: 0) {
+            // Title bar
+            HStack {
+                Text("设置")
+                    .font(Theme.titleFont).foregroundColor(Theme.textPrimary)
+                Spacer()
+                Button { dismiss() } label: {
+                    Image(systemName: "xmark.circle.fill")
+                        .font(.system(size: 20)).foregroundColor(Theme.textTertiary)
+                }
+                .buttonStyle(.plain)
+            }
+            .padding(20)
+
+            Divider()
+
+            Form {
+                // ── eLearning ──────────────────────────────────
+                Section {
+                    if eLearning.isLoggedIn {
+                        HStack(spacing: 10) {
+                            Image(systemName: "checkmark.circle.fill")
+                                .foregroundColor(Theme.success)
+                            VStack(alignment: .leading, spacing: 2) {
+                                Text("已连接 Fudan eLearning")
+                                    .font(Theme.bodyFont).foregroundColor(Theme.textPrimary)
+                                if let d = eLearning.lastSyncDate {
+                                    Text("上次同步：\(d, style: .relative)前")
+                                        .font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                                }
+                            }
+                            Spacer()
+                            Button("立即同步") { Task { await eLearning.syncAll() } }
+                                .buttonStyle(.bordered)
+                            Button("退出登录", role: .destructive) { eLearning.logout() }
+                                .buttonStyle(.bordered)
+                        }
+
+                        Picker("自动同步频率", selection: $syncInterval) {
+                            Text("每 15 分钟").tag(15)
+                            Text("每 30 分钟").tag(30)
+                            Text("每 1 小时").tag(60)
+                            Text("不自动同步").tag(0)
+                        }
+                        .onChange(of: syncInterval) { new in
+                            eLearning.startAutoSync(intervalMinutes: new)
+                        }
+
+                        let newCount = eLearning.resources.filter(\.isNew).count
+                        if newCount > 0 {
+                            Label("\(newCount) 个未查看的新内容", systemImage: "bell.badge")
+                                .font(Theme.captionFont)
+                                .foregroundColor(Theme.warning)
+                        }
+
+                    } else {
+                        // Login form
+                        TextField("学号 / 用户名", text: $username)
+                        SecureField("密码", text: $password)
+
+                        HStack {
+                            Button {
+                                isLoggingIn = true
+                                Task {
+                                    _ = await eLearning.login(username: username, password: password)
+                                    isLoggingIn = false
+                                    if eLearning.isLoggedIn { password = "" }
+                                }
+                            } label: {
+                                HStack {
+                                    if isLoggingIn { ProgressView().scaleEffect(0.7) }
+                                    Text("登录 eLearning")
+                                }
+                            }
+                            .disabled(username.isEmpty || password.isEmpty || isLoggingIn)
+                            .buttonStyle(.borderedProminent)
+                            .tint(Theme.accent)
+
+                            Spacer()
+                        }
+
+                        if let err = eLearning.errorMessage {
+                            Text(err)
+                                .font(Theme.captionFont)
+                                .foregroundColor(Theme.danger)
+                        }
+
+                        Text("账号密码仅存储于本地 macOS Keychain，不会上传至任何服务器。")
+                            .font(Theme.captionFont)
+                            .foregroundColor(Theme.textTertiary)
+                    }
+                } header: {
+                    Text("eLearning 集成")
+                }
+
+                // ── Data ──────────────────────────────────────
+                Section {
+                    HStack {
+                        Text("课程数据")
+                        Spacer()
+                        Text("~/Library/Application Support/TodoFlow/")
+                            .font(Theme.captionFont).foregroundColor(Theme.textTertiary)
+                    }
+                    Button("重置为示例数据", role: .destructive) {
+                        // Clear existing and reload sample data
+                        store.courses = []
+                        store.activities = []
+                        store.save()
+                        store.load()
+                    }
+                } header: {
+                    Text("数据")
+                }
+
+                // ── About ─────────────────────────────────────
+                Section {
+                    HStack {
+                        Text("版本")
+                        Spacer()
+                        Text("1.0.0").foregroundColor(Theme.textSecondary)
+                    }
+                    HStack {
+                        Text("作者")
+                        Spacer()
+                        Text("TodoFlow").foregroundColor(Theme.textSecondary)
+                    }
+                    Text("专为复旦学子设计的学期整理工具。支持课程管理、本地文件展示、eLearning 更新追踪与活动便利贴。")
+                        .font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                } header: {
+                    Text("关于")
+                }
+            }
+            .formStyle(.grouped)
+        }
+        .frame(width: 520, height: 500)
+        .background(Theme.background)
+        .onAppear {
+            eLearning.restoreSession()
+        }
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/Sheets.swift b/TodoFlow/Sources/TodoFlow/Views/Sheets.swift
new file mode 100644
index 0000000..d7ca2cf
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/Sheets.swift
@@ -0,0 +1,400 @@
+import SwiftUI
+import AppKit
+
+// ─────────────────────────────────────────────
+// MARK: - AddCourseSheet
+// ─────────────────────────────────────────────
+
+struct AddCourseSheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+
+    @State private var name        = ""
+    @State private var code        = ""
+    @State private var professor   = ""
+    @State private var colorHex    = "3B82F6"
+    @State private var folderPath  = ""
+    @State private var eLearningId = ""
+
+    private let presetColors = [
+        "3B82F6", "10B981", "F59E0B", "EF4444",
+        "8B5CF6", "EC4899", "06B6D4", "84CC16",
+    ]
+
+    var body: some View {
+        SheetContainer(title: "添加课程", onCancel: dismiss.callAsFunction) {
+            Button("添加") {
+                var c = Course(name: name, code: code, professor: professor, colorHex: colorHex)
+                if !folderPath.isEmpty  { c.folderPath = folderPath }
+                if let id = Int(eLearningId) { c.eLearningCourseId = id }
+                store.addCourse(c)
+                dismiss()
+            }
+            .disabled(name.isEmpty || code.isEmpty)
+            .buttonStyle(.borderedProminent).tint(Theme.accent)
+        } content: {
+            VStack(spacing: 14) {
+                SheetField(label: "课程名称", placeholder: "例：数据结构", text: $name)
+                SheetField(label: "课程代码", placeholder: "例：CS101", text: $code)
+                SheetField(label: "任课教师", placeholder: "例：张教授", text: $professor)
+
+                // Color picker
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("颜色").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    HStack(spacing: 10) {
+                        ForEach(presetColors, id: \.self) { hex in
+                            Circle()
+                                .fill(Color(hex: hex))
+                                .frame(width: 24, height: 24)
+                                .overlay(
+                                    Circle().stroke(colorHex == hex ? Theme.textPrimary : Color.clear, lineWidth: 2)
+                                )
+                                .onTapGesture { colorHex = hex }
+                        }
+                    }
+                }
+
+                SheetField(label: "本地文件夹路径（留空则默认 ~/Desktop/<课程名>）", placeholder: "/Users/you/Desktop/数据结构", text: $folderPath)
+                SheetField(label: "eLearning Moodle 课程 ID（可选）", placeholder: "例：12345", text: $eLearningId)
+            }
+        }
+    }
+}
+
+// ─────────────────────────────────────────────
+// MARK: - EditCourseSheet
+// ─────────────────────────────────────────────
+
+struct EditCourseSheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+
+    let course: Course
+
+    @State private var name        = ""
+    @State private var code        = ""
+    @State private var professor   = ""
+    @State private var colorHex    = ""
+    @State private var folderPath  = ""
+    @State private var eLearningId = ""
+
+    private let presetColors = [
+        "3B82F6", "10B981", "F59E0B", "EF4444",
+        "8B5CF6", "EC4899", "06B6D4", "84CC16",
+    ]
+
+    var body: some View {
+        SheetContainer(title: "编辑课程", onCancel: dismiss.callAsFunction) {
+            HStack(spacing: 8) {
+                Button("删除课程", role: .destructive) {
+                    store.deleteCourse(course)
+                    dismiss()
+                }
+                .buttonStyle(.bordered)
+                Spacer()
+                Button("保存") {
+                    var c = course
+                    c.name = name; c.code = code; c.professor = professor; c.colorHex = colorHex
+                    c.folderPath = folderPath.isEmpty ? nil : folderPath
+                    c.eLearningCourseId = Int(eLearningId)
+                    store.updateCourse(c)
+                    dismiss()
+                }
+                .disabled(name.isEmpty || code.isEmpty)
+                .buttonStyle(.borderedProminent).tint(Theme.accent)
+            }
+        } content: {
+            VStack(spacing: 14) {
+                SheetField(label: "课程名称", placeholder: "例：数据结构", text: $name)
+                SheetField(label: "课程代码", placeholder: "例：CS101", text: $code)
+                SheetField(label: "任课教师", placeholder: "例：张教授", text: $professor)
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("颜色").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    HStack(spacing: 10) {
+                        ForEach(presetColors, id: \.self) { hex in
+                            Circle()
+                                .fill(Color(hex: hex))
+                                .frame(width: 24, height: 24)
+                                .overlay(Circle().stroke(colorHex == hex ? Theme.textPrimary : Color.clear, lineWidth: 2))
+                                .onTapGesture { colorHex = hex }
+                        }
+                    }
+                }
+
+                SheetField(label: "本地文件夹路径", placeholder: "/Users/you/Desktop/数据结构", text: $folderPath)
+                SheetField(label: "eLearning Moodle 课程 ID（可选）", placeholder: "例：12345", text: $eLearningId)
+            }
+        }
+        .onAppear {
+            name        = course.name
+            code        = course.code
+            professor   = course.professor
+            colorHex    = course.colorHex
+            folderPath  = course.folderPath ?? ""
+            eLearningId = course.eLearningCourseId.map(String.init) ?? ""
+        }
+    }
+}
+
+// ─────────────────────────────────────────────
+// MARK: - AddAssignmentSheet
+// ─────────────────────────────────────────────
+
+struct AddAssignmentSheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+
+    let courseId: UUID
+
+    @State private var title   = ""
+    @State private var dueDate = Date()
+    @State private var notes   = ""
+
+    var body: some View {
+        SheetContainer(title: "添加作业 / DDL", onCancel: dismiss.callAsFunction) {
+            Button("添加") {
+                let a = Assignment(title: title, dueDate: dueDate, courseId: courseId, notes: notes)
+                store.addAssignment(a)
+                dismiss()
+            }
+            .disabled(title.isEmpty)
+            .buttonStyle(.borderedProminent).tint(Theme.accent)
+        } content: {
+            VStack(spacing: 14) {
+                SheetField(label: "作业标题", placeholder: "例：第三章习题集", text: $title)
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("截止日期").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    DatePicker("", selection: $dueDate, displayedComponents: [.date, .hourAndMinute])
+                        .labelsHidden()
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("备注（可选）").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    TextEditor(text: $notes)
+                        .font(Theme.bodyFont)
+                        .frame(height: 60)
+                        .padding(8)
+                        .background(Theme.inputBg)
+                        .cornerRadius(8)
+                        .scrollContentBackground(.hidden)
+                }
+            }
+        }
+    }
+}
+
+// ─────────────────────────────────────────────
+// MARK: - AddActivitySheet
+// ─────────────────────────────────────────────
+
+struct AddActivitySheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+
+    @State private var title       = ""
+    @State private var description = ""
+    @State private var category    = "项目"
+    @State private var startDate   = Date()
+    @State private var hasEndDate  = false
+    @State private var endDate     = Date()
+
+    var body: some View {
+        SheetContainer(title: "添加活动 / 项目", onCancel: dismiss.callAsFunction) {
+            Button("添加") {
+                let a = Activity(
+                    title: title,
+                    startDate: startDate,
+                    endDate: hasEndDate ? endDate : nil,
+                    description: description,
+                    category: category
+                )
+                store.addActivity(a)
+                dismiss()
+            }
+            .disabled(title.isEmpty)
+            .buttonStyle(.borderedProminent).tint(Theme.accent)
+        } content: {
+            VStack(spacing: 14) {
+                SheetField(label: "标题", placeholder: "例：学生会策划会议", text: $title)
+
+                VStack(alignment: .leading, spacing: 8) {
+                    Text("类型").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    SheetField(label: "", placeholder: "自定义类型，例：比赛、实习…", text: $category)
+                    // Quick-pick suggestion chips
+                    ScrollView(.horizontal, showsIndicators: false) {
+                        HStack(spacing: 8) {
+                            ForEach(Activity.suggestedCategories, id: \.self) { s in
+                                Text(s)
+                                    .font(Theme.captionFont)
+                                    .padding(.horizontal, 10).padding(.vertical, 5)
+                                    .background(category == s ? Theme.accent.opacity(0.15) : Theme.inputBg)
+                                    .foregroundColor(category == s ? Theme.accent : Theme.textSecondary)
+                                    .cornerRadius(16)
+                                    .onTapGesture { category = s }
+                            }
+                        }
+                    }
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("开始日期").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    DatePicker("", selection: $startDate, displayedComponents: [.date])
+                        .labelsHidden()
+                }
+
+                Toggle("设置截止 / 结束日期", isOn: $hasEndDate)
+                if hasEndDate {
+                    VStack(alignment: .leading, spacing: 6) {
+                        Text("结束日期").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                        DatePicker("", selection: $endDate, in: startDate..., displayedComponents: [.date])
+                            .labelsHidden()
+                    }
+                }
+
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("描述（可选）").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    TextEditor(text: $description)
+                        .font(Theme.bodyFont)
+                        .frame(height: 60)
+                        .padding(8)
+                        .background(Theme.inputBg)
+                        .cornerRadius(8)
+                        .scrollContentBackground(.hidden)
+                }
+            }
+        }
+    }
+}
+
+// ─────────────────────────────────────────────
+// MARK: - AddStickyNoteSheet
+// ─────────────────────────────────────────────
+
+struct AddStickyNoteSheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @EnvironmentObject var store: AppStore
+
+    let activityId: UUID
+
+    @State private var content   = ""
+    @State private var noteColor = StickyNote.StickyColor.yellow
+
+    var body: some View {
+        SheetContainer(title: "添加便利贴", onCancel: dismiss.callAsFunction) {
+            Button("添加") {
+                let n = StickyNote(content: content, colorName: noteColor, activityId: activityId)
+                store.addStickyNote(n, to: activityId)
+                dismiss()
+            }
+            .disabled(content.isEmpty)
+            .buttonStyle(.borderedProminent).tint(Theme.accent)
+        } content: {
+            VStack(spacing: 14) {
+                // Color selector
+                VStack(alignment: .leading, spacing: 8) {
+                    Text("颜色").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    HStack(spacing: 10) {
+                        ForEach(StickyNote.StickyColor.allCases, id: \.self) { c in
+                            ZStack {
+                                Circle().fill(Theme.stickyColor(c)).frame(width: 30, height: 30)
+                                if c == noteColor {
+                                    Circle().stroke(Theme.textPrimary.opacity(0.4), lineWidth: 2).frame(width: 30, height: 30)
+                                    Image(systemName: "checkmark").font(.system(size: 10, weight: .bold)).foregroundColor(.gray)
+                                }
+                            }
+                            .onTapGesture { noteColor = c }
+                        }
+                    }
+                }
+
+                // Content
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("内容").font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+                    ZStack(alignment: .topLeading) {
+                        RoundedRectangle(cornerRadius: 10)
+                            .fill(Theme.stickyColor(noteColor))
+                        if content.isEmpty {
+                            Text("写下你的想法、会议记录、提醒…")
+                                .font(Theme.bodyFont).foregroundColor(.gray.opacity(0.5))
+                                .padding(10)
+                        }
+                        TextEditor(text: $content)
+                            .font(Theme.bodyFont)
+                            .frame(minHeight: 100)
+                            .padding(6)
+                            .scrollContentBackground(.hidden)
+                            .background(Color.clear)
+                    }
+                    .frame(minHeight: 110)
+                }
+            }
+        }
+    }
+}
+
+// ─────────────────────────────────────────────
+// MARK: - Shared sheet scaffolding
+// ─────────────────────────────────────────────
+
+struct SheetContainer<Content: View, Trailing: View>: View {
+    let title: String
+    let onCancel: () -> Void
+    @ViewBuilder var trailing: () -> Trailing
+    @ViewBuilder var content: () -> Content
+
+    var body: some View {
+        VStack(spacing: 0) {
+            // Navigation-style header
+            HStack {
+                Button("取消", action: onCancel)
+                    .buttonStyle(.plain)
+                    .foregroundColor(Theme.textSecondary)
+                Spacer()
+                Text(title)
+                    .font(Theme.headlineFont).foregroundColor(Theme.textPrimary)
+                Spacer()
+                trailing()
+            }
+            .padding(20)
+
+            Divider()
+
+            ScrollView {
+                content()
+                    .padding(20)
+            }
+        }
+        .frame(minWidth: 460, maxWidth: 520)
+        .background(Theme.background)
+        .onAppear {
+            // Make the sheet window key so TextFields accept keyboard input on macOS
+            NSApp.activate(ignoringOtherApps: true)
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
+                NSApp.windows
+                    .filter { $0.isVisible && $0.canBecomeKey }
+                    .max(by: { $0.windowNumber < $1.windowNumber })?
+                    .makeKeyAndOrderFront(nil)
+            }
+        }
+    }
+}
+
+struct SheetField: View {
+    let label: String
+    let placeholder: String
+    @Binding var text: String
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 5) {
+            Text(label).font(Theme.captionFont).foregroundColor(Theme.textSecondary)
+            TextField(placeholder, text: $text)
+                .textFieldStyle(.plain)
+                .font(Theme.bodyFont)
+                .padding(10)
+                .background(Theme.inputBg)
+                .cornerRadius(8)
+        }
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/Views/SidebarView.swift b/TodoFlow/Sources/TodoFlow/Views/SidebarView.swift
new file mode 100644
index 0000000..ebb7052
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/Views/SidebarView.swift
@@ -0,0 +1,168 @@
+import SwiftUI
+
+struct SidebarView: View {
+    @Binding var selectedTab: AppTab
+    @Binding var showSettings: Bool
+    @EnvironmentObject var store: AppStore
+    @EnvironmentObject var eLearning: ELearningService
+
+    var body: some View {
+        VStack(spacing: 0) {
+
+            // ── App logo ──────────────────────────────────────
+            HStack(spacing: 10) {
+                ZStack {
+                    RoundedRectangle(cornerRadius: 8)
+                        .fill(Theme.accent)
+                        .frame(width: 30, height: 30)
+                    Image(systemName: "checkmark.circle.fill")
+                        .foregroundColor(.white)
+                        .font(.system(size: 16, weight: .semibold))
+                }
+                Text("TodoFlow")
+                    .font(.system(size: 15, weight: .bold))
+                    .foregroundColor(Theme.textPrimary)
+                Spacer()
+            }
+            .padding(.horizontal, 14)
+            .padding(.top, 18)
+            .padding(.bottom, 14)
+
+            Divider().padding(.horizontal, 10)
+
+            // ── Navigation ────────────────────────────────────
+            VStack(spacing: 2) {
+                ForEach(AppTab.allCases, id: \.self) { tab in
+                    SidebarItem(
+                        tab: tab,
+                        isSelected: selectedTab == tab,
+                        badge: tab == .courses ? store.upcomingCount : 0
+                    )
+                    .onTapGesture { selectedTab = tab }
+                }
+            }
+            .padding(.horizontal, 8)
+            .padding(.vertical, 8)
+
+            Divider().padding(.horizontal, 10)
+
+            // ── Upcoming deadlines preview ────────────────────
+            let upcoming = upcomingItems
+            if !upcoming.isEmpty {
+                VStack(alignment: .leading, spacing: 6) {
+                    Text("即将到期")
+                        .sectionHeader()
+                        .padding(.horizontal, 10)
+                        .padding(.top, 10)
+
+                    ForEach(upcoming.prefix(5)) { event in
+                        HStack(spacing: 8) {
+                            Circle()
+                                .fill(Color(hex: event.colorHex))
+                                .frame(width: 6, height: 6)
+                            Text(event.title)
+                                .font(Theme.captionFont)
+                                .foregroundColor(Theme.textSecondary)
+                                .lineLimit(1)
+                            Spacer()
+                            Text(event.date, style: .relative)
+                                .font(.system(size: 10))
+                                .foregroundColor(Theme.textTertiary)
+                        }
+                        .padding(.horizontal, 14)
+                    }
+                }
+                .padding(.bottom, 8)
+            }
+
+            // ── eLearning new-items badge ─────────────────────
+            let newCount = eLearning.resources.filter(\.isNew).count
+            if newCount > 0 {
+                HStack(spacing: 8) {
+                    Image(systemName: "link.badge.plus")
+                        .foregroundColor(Theme.accent)
+                        .font(.system(size: 12))
+                    Text("\(newCount) 个 eLearning 新内容")
+                        .font(Theme.captionFont)
+                        .foregroundColor(Theme.textSecondary)
+                    Spacer()
+                }
+                .padding(.horizontal, 14)
+                .padding(.vertical, 8)
+                .background(Theme.accentLight)
+                .cornerRadius(8)
+                .padding(.horizontal, 8)
+                .padding(.bottom, 4)
+            }
+
+            Spacer()
+
+            Divider().padding(.horizontal, 10)
+
+            // ── Settings button ───────────────────────────────
+            Button { showSettings = true } label: {
+                HStack(spacing: 10) {
+                    Image(systemName: "gearshape")
+                        .font(.system(size: 13))
+                        .foregroundColor(Theme.textSecondary)
+                    Text("设置")
+                        .font(Theme.bodyFont)
+                        .foregroundColor(Theme.textSecondary)
+                    Spacer()
+                    if eLearning.isLoggedIn {
+                        Circle().fill(Theme.success).frame(width: 7, height: 7)
+                    }
+                }
+                .padding(.horizontal, 14)
+                .padding(.vertical, 11)
+            }
+            .buttonStyle(.plain)
+        }
+        .background(Theme.sidebarBg)
+    }
+
+    private var upcomingItems: [CalendarEvent] {
+        let horizon = Calendar.current.date(byAdding: .day, value: 7, to: Date())!
+        return store.calendarEvents.filter { $0.date >= Date() && $0.date <= horizon }
+    }
+}
+
+// MARK: - Sidebar Item
+
+struct SidebarItem: View {
+    let tab: AppTab
+    let isSelected: Bool
+    let badge: Int
+
+    var body: some View {
+        HStack(spacing: 10) {
+            Image(systemName: tab.icon)
+                .font(.system(size: 13, weight: isSelected ? .semibold : .regular))
+                .foregroundColor(isSelected ? Theme.accent : Theme.textSecondary)
+                .frame(width: 18)
+
+            Text(tab.rawValue)
+                .font(.system(size: 13, weight: isSelected ? .semibold : .regular))
+                .foregroundColor(isSelected ? Theme.textPrimary : Theme.textSecondary)
+
+            Spacer()
+
+            if badge > 0 {
+                Text("\(min(badge, 99))")
+                    .font(.system(size: 10, weight: .bold))
+                    .foregroundColor(.white)
+                    .padding(.horizontal, 5)
+                    .padding(.vertical, 1)
+                    .background(Theme.danger)
+                    .clipShape(Capsule())
+            }
+        }
+        .padding(.horizontal, 10)
+        .padding(.vertical, 7)
+        .background(
+            RoundedRectangle(cornerRadius: 7)
+                .fill(isSelected ? Theme.accent.opacity(0.12) : Color.clear)
+        )
+        .contentShape(Rectangle())
+    }
+}
diff --git a/TodoFlow/Sources/TodoFlow/main.swift b/TodoFlow/Sources/TodoFlow/main.swift
new file mode 100644
index 0000000..6c33aba
--- /dev/null
+++ b/TodoFlow/Sources/TodoFlow/main.swift
@@ -0,0 +1,44 @@
+import SwiftUI
+
+// MARK: - App definition
+// Note: in an SPM executableTarget, @main is not used.
+// We define the App struct here and call .main() explicitly.
+
+struct TodoFlowApp: App {
+
+    @StateObject private var store     = AppStore()
+    @StateObject private var eLearning = ELearningService()
+
+    var body: some Scene {
+        WindowGroup {
+            ContentView()
+                .environmentObject(store)
+                .environmentObject(eLearning)
+                .frame(minWidth: 900, minHeight: 600)
+                .onAppear {
+                    eLearning.restoreSession()
+                }
+        }
+        .windowStyle(.titleBar)
+        .windowToolbarStyle(.unified(showsTitle: false))
+        .commands {
+            CommandGroup(replacing: .newItem) {}   // hide default "New Window"
+            CommandMenu("TodoFlow") {
+                Button("日历") {}
+                    .keyboardShortcut("1", modifiers: .command)
+                Button("课程") {}
+                    .keyboardShortcut("2", modifiers: .command)
+                Button("活动 & 项目") {}
+                    .keyboardShortcut("3", modifiers: .command)
+            }
+        }
+
+        Settings {
+            SettingsView()
+                .environmentObject(store)
+                .environmentObject(eLearning)
+        }
+    }
+}
+
+TodoFlowApp.main()