diff --git a/package.json b/package.json
index 0b18cfa..1e941c8 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "nextcloud-notes-tauri",
   "private": true,
-  "version": "0.1.2",
+  "version": "0.1.3",
   "type": "module",
   "scripts": {
     "dev": "vite",
diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index a8b7110..64cf905 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Nextcloud Notes",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "identifier": "com.davidrelich.nextcloud-notes",
   "build": {
     "beforeDevCommand": "npm run dev",
diff --git a/src/App.tsx b/src/App.tsx
index 772f403..3926272 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -5,6 +5,9 @@ import { NoteEditor } from './components/NoteEditor';
 import { CategoriesSidebar } from './components/CategoriesSidebar';
 import { NextcloudAPI } from './api/nextcloud';
 import { Note } from './types';
+import { syncManager, SyncStatus } from './services/syncManager';
+import { localDB } from './db/localDB';
+import { useOnlineStatus } from './hooks/useOnlineStatus';
 
 function App() {
   const [isLoggedIn, setIsLoggedIn] = useState(false);
@@ -25,43 +28,60 @@ function App() {
   const [editorFontSize, setEditorFontSize] = useState(14);
   const [previewFont, setPreviewFont] = useState('Merriweather');
   const [previewFontSize, setPreviewFontSize] = useState(16);
+  const [syncStatus, setSyncStatus] = useState<SyncStatus>('idle');
+  const [pendingSyncCount, setPendingSyncCount] = useState(0);
+  const isOnline = useOnlineStatus();
 
   useEffect(() => {
-    const savedServer = localStorage.getItem('serverURL');
-    const savedUsername = localStorage.getItem('username');
-    const savedPassword = localStorage.getItem('password');
-    const savedTheme = localStorage.getItem('theme') as 'light' | 'dark' | 'system' | null;
-    const savedEditorFont = localStorage.getItem('editorFont');
-    const savedPreviewFont = localStorage.getItem('previewFont');
+    const initApp = async () => {
+      await localDB.init();
+      
+      const savedServer = localStorage.getItem('serverURL');
+      const savedUsername = localStorage.getItem('username');
+      const savedPassword = localStorage.getItem('password');
+      const savedTheme = localStorage.getItem('theme') as 'light' | 'dark' | 'system' | null;
+      const savedEditorFont = localStorage.getItem('editorFont');
+      const savedPreviewFont = localStorage.getItem('previewFont');
 
-    if (savedTheme) {
-      setTheme(savedTheme);
-    }
-    if (savedEditorFont) {
-      setEditorFont(savedEditorFont);
-    }
-    if (savedPreviewFont) {
-      setPreviewFont(savedPreviewFont);
-    }
-    const savedEditorFontSize = localStorage.getItem('editorFontSize');
-    const savedPreviewFontSize = localStorage.getItem('previewFontSize');
-    if (savedEditorFontSize) {
-      setEditorFontSize(parseInt(savedEditorFontSize, 10));
-    }
-    if (savedPreviewFontSize) {
-      setPreviewFontSize(parseInt(savedPreviewFontSize, 10));
-    }
+      if (savedTheme) {
+        setTheme(savedTheme);
+      }
+      if (savedEditorFont) {
+        setEditorFont(savedEditorFont);
+      }
+      if (savedPreviewFont) {
+        setPreviewFont(savedPreviewFont);
+      }
+      const savedEditorFontSize = localStorage.getItem('editorFontSize');
+      const savedPreviewFontSize = localStorage.getItem('previewFontSize');
+      if (savedEditorFontSize) {
+        setEditorFontSize(parseInt(savedEditorFontSize, 10));
+      }
+      if (savedPreviewFontSize) {
+        setPreviewFontSize(parseInt(savedPreviewFontSize, 10));
+      }
 
-    if (savedServer && savedUsername && savedPassword) {
-      const apiInstance = new NextcloudAPI({
-        serverURL: savedServer,
-        username: savedUsername,
-        password: savedPassword,
-      });
-      setApi(apiInstance);
-      setUsername(savedUsername);
-      setIsLoggedIn(true);
-    }
+      if (savedServer && savedUsername && savedPassword) {
+        const apiInstance = new NextcloudAPI({
+          serverURL: savedServer,
+          username: savedUsername,
+          password: savedPassword,
+        });
+        setApi(apiInstance);
+        syncManager.setAPI(apiInstance);
+        setUsername(savedUsername);
+        setIsLoggedIn(true);
+        
+        // Load notes from local DB immediately
+        const localNotes = await localDB.getAllNotes();
+        if (localNotes.length > 0) {
+          setNotes(localNotes.sort((a, b) => b.modified - a.modified));
+          setSelectedNoteId(localNotes[0].id);
+        }
+      }
+    };
+    
+    initApp();
   }, []);
 
   useEffect(() => {
@@ -88,43 +108,62 @@ function App() {
     document.documentElement.classList.toggle('dark', effectiveTheme === 'dark');
   }, [effectiveTheme]);
 
+  useEffect(() => {
+    syncManager.setStatusCallback((status, count) => {
+      setSyncStatus(status);
+      setPendingSyncCount(count);
+    });
+  }, []);
+
   useEffect(() => {
     if (api && isLoggedIn) {
-      syncNotes();
-      const interval = setInterval(syncNotes, 300000);
+      loadNotes();
+      const interval = setInterval(() => syncNotes(), 300000);
       return () => clearInterval(interval);
     }
   }, [api, isLoggedIn]);
 
-  const syncNotes = async () => {
-    if (!api) return;
+  const loadNotes = async () => {
     try {
-      const fetched = await api.fetchNotes();
-      setNotes(fetched.sort((a, b) => b.modified - a.modified));
-      if (!selectedNoteId && fetched.length > 0) {
-        setSelectedNoteId(fetched[0].id);
+      const loadedNotes = await syncManager.loadNotes();
+      setNotes(loadedNotes.sort((a, b) => b.modified - a.modified));
+      if (!selectedNoteId && loadedNotes.length > 0) {
+        setSelectedNoteId(loadedNotes[0].id);
       }
+    } catch (error) {
+      console.error('Failed to load notes:', error);
+    }
+  };
+
+  const syncNotes = async () => {
+    try {
+      await syncManager.syncWithServer();
+      await loadNotes();
     } catch (error) {
       console.error('Sync failed:', error);
     }
   };
 
-  const handleLogin = (serverURL: string, username: string, password: string) => {
+  const handleLogin = async (serverURL: string, username: string, password: string) => {
     localStorage.setItem('serverURL', serverURL);
     localStorage.setItem('username', username);
     localStorage.setItem('password', password);
 
     const apiInstance = new NextcloudAPI({ serverURL, username, password });
     setApi(apiInstance);
+    syncManager.setAPI(apiInstance);
     setUsername(username);
     setIsLoggedIn(true);
   };
 
-  const handleLogout = () => {
+  const handleLogout = async () => {
     localStorage.removeItem('serverURL');
     localStorage.removeItem('username');
     localStorage.removeItem('password');
+    await localDB.clearNotes();
+    await localDB.clearSyncQueue();
     setApi(null);
+    syncManager.setAPI(null);
     setUsername('');
     setNotes([]);
     setSelectedNoteId(null);
@@ -157,7 +196,6 @@ function App() {
   };
 
   const handleCreateNote = async () => {
-    if (!api) return;
     try {
       const timestamp = new Date().toLocaleString('en-US', {
         year: 'numeric',
@@ -168,7 +206,7 @@ function App() {
         hour12: false,
       }).replace(/[/:]/g, '-').replace(', ', ' ');
       
-      const note = await api.createNote(`New Note ${timestamp}`, '', selectedCategory);
+      const note = await syncManager.createNote(`New Note ${timestamp}`, '', selectedCategory);
       setNotes([note, ...notes]);
       setSelectedNoteId(note.id);
     } catch (error) {
@@ -183,28 +221,21 @@ function App() {
   };
 
   const handleUpdateNote = async (updatedNote: Note) => {
-    if (!api) return;
     try {
-      console.log('Sending to API - content length:', updatedNote.content.length);
-      console.log('Sending to API - last 50 chars:', updatedNote.content.slice(-50));
-      const result = await api.updateNote(updatedNote);
-      console.log('Received from API - content length:', result.content.length);
-      console.log('Received from API - last 50 chars:', result.content.slice(-50));
-      // Update notes array with server response now that we have manual save
-      setNotes(notes.map(n => n.id === result.id ? result : n));
+      await syncManager.updateNote(updatedNote);
+      setNotes(notes.map(n => n.id === updatedNote.id ? updatedNote : n));
     } catch (error) {
       console.error('Update note failed:', error);
     }
   };
 
   const handleDeleteNote = async (note: Note) => {
-    if (!api) return;
-    
     try {
-      await api.deleteNote(note.id);
-      setNotes(notes.filter(n => n.id !== note.id));
+      await syncManager.deleteNote(note.id);
+      const remainingNotes = notes.filter(n => n.id !== note.id);
+      setNotes(remainingNotes);
       if (selectedNoteId === note.id) {
-        setSelectedNoteId(notes[0]?.id || null);
+        setSelectedNoteId(remainingNotes[0]?.id || null);
       }
     } catch (error) {
       console.error('Delete note failed:', error);
@@ -267,6 +298,9 @@ function App() {
             showFavoritesOnly={showFavoritesOnly}
             onToggleFavorites={() => setShowFavoritesOnly(!showFavoritesOnly)}
             hasUnsavedChanges={hasUnsavedChanges}
+            syncStatus={syncStatus}
+            pendingSyncCount={pendingSyncCount}
+            isOnline={isOnline}
           />
         </>
       )}
diff --git a/src/components/NoteEditor.tsx b/src/components/NoteEditor.tsx
index 784fde2..9d2c714 100644
--- a/src/components/NoteEditor.tsx
+++ b/src/components/NoteEditor.tsx
@@ -38,6 +38,7 @@ export function NoteEditor({ note, onUpdateNote, onUnsavedChanges, categories, i
   const [isLoadingImages, setIsLoadingImages] = useState(false);
   const [isUploading, setIsUploading] = useState(false);
   const previousNoteIdRef = useRef<number | null>(null);
+  const previousNoteContentRef = useRef<string>('');
   const textareaRef = useRef<HTMLTextAreaElement>(null);
   const fileInputRef = useRef<HTMLInputElement>(null);
 
@@ -131,12 +132,12 @@ export function NoteEditor({ note, onUpdateNote, onUnsavedChanges, categories, i
   useEffect(() => {
     const loadNewNote = () => {
       if (note) {
-        console.log(`[Note ${note.id}] Loading note. Title: "${note.title}", Content length: ${note.content.length}`);
         setLocalTitle(note.title);
         setLocalContent(note.content);
         setLocalCategory(note.category || '');
         setLocalFavorite(note.favorite);
         setHasUnsavedChanges(false);
+        setIsPreviewMode(false);
         setProcessedContent(''); // Clear preview content immediately
         
         const firstLine = note.content.split('\n')[0].replace(/^#+\s*/, '').trim();
@@ -144,21 +145,29 @@ export function NoteEditor({ note, onUpdateNote, onUnsavedChanges, categories, i
         setTitleManuallyEdited(!titleMatchesFirstLine);
         
         previousNoteIdRef.current = note.id;
+        previousNoteContentRef.current = note.content;
       }
     };
 
+    // Switching to a different note
     if (previousNoteIdRef.current !== null && previousNoteIdRef.current !== note?.id) {
       console.log(`Switching from note ${previousNoteIdRef.current} to note ${note?.id}`);
-      // Clear preview content immediately when switching notes
       setProcessedContent('');
       if (hasUnsavedChanges) {
         handleSave();
       }
       loadNewNote();
-    } else {
+    } 
+    // Same note but content changed from server (and no unsaved local changes)
+    else if (note && previousNoteIdRef.current === note.id && !hasUnsavedChanges && previousNoteContentRef.current !== note.content) {
+      console.log(`Note ${note.id} content changed from server (prev: ${previousNoteContentRef.current.length} chars, new: ${note.content.length} chars)`);
       loadNewNote();
     }
-  }, [note?.id]);
+    // Initial load
+    else if (!note || previousNoteIdRef.current === null) {
+      loadNewNote();
+    }
+  }, [note?.id, note?.content, note?.modified]);
 
   const handleSave = () => {
     if (!note || !hasUnsavedChanges) return;
diff --git a/src/components/NotesList.tsx b/src/components/NotesList.tsx
index 2c787b7..ec0f7c1 100644
--- a/src/components/NotesList.tsx
+++ b/src/components/NotesList.tsx
@@ -1,5 +1,6 @@
 import React from 'react';
 import { Note } from '../types';
+import { SyncStatus } from '../services/syncManager';
 
 interface NotesListProps {
   notes: Note[];
@@ -13,6 +14,9 @@ interface NotesListProps {
   showFavoritesOnly: boolean;
   onToggleFavorites: () => void;
   hasUnsavedChanges: boolean;
+  syncStatus: SyncStatus;
+  pendingSyncCount: number;
+  isOnline: boolean;
 }
 
 export function NotesList({
@@ -27,6 +31,9 @@ export function NotesList({
   showFavoritesOnly,
   onToggleFavorites,
   hasUnsavedChanges,
+  syncStatus: _syncStatus,
+  pendingSyncCount,
+  isOnline,
 }: NotesListProps) {
   const [isSyncing, setIsSyncing] = React.useState(false);
   const [deleteClickedId, setDeleteClickedId] = React.useState<number | null>(null);
@@ -117,7 +124,22 @@ export function NotesList({
     >
       <div className="p-4 border-b border-gray-200 dark:border-gray-700">
         <div className="flex items-center justify-between mb-3">
-          <h2 className="text-lg font-semibold text-gray-900 dark:text-gray-100">Notes</h2>
+          <div className="flex items-center gap-2">
+            <h2 className="text-lg font-semibold text-gray-900 dark:text-gray-100">Notes</h2>
+            {!isOnline && (
+              <span className="px-2 py-0.5 text-xs font-medium bg-orange-100 dark:bg-orange-900 text-orange-700 dark:text-orange-300 rounded-full flex items-center gap-1">
+                <svg className="w-3 h-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M18.364 5.636a9 9 0 010 12.728m0 0l-2.829-2.829m2.829 2.829L21 21M15.536 8.464a5 5 0 010 7.072m0 0l-2.829-2.829m-4.243 2.829a4.978 4.978 0 01-1.414-2.83m-1.414 5.658a9 9 0 01-2.167-9.238m7.824 2.167a1 1 0 111.414 1.414m-1.414-1.414L3 3" />
+                </svg>
+                Offline
+              </span>
+            )}
+            {pendingSyncCount > 0 && (
+              <span className="px-2 py-0.5 text-xs font-medium bg-blue-100 dark:bg-blue-900 text-blue-700 dark:text-blue-300 rounded-full">
+                {pendingSyncCount} pending
+              </span>
+            )}
+          </div>
           <div className="flex items-center space-x-1">
             <button
               onClick={handleSync}
diff --git a/src/db/localDB.ts b/src/db/localDB.ts
new file mode 100644
index 0000000..0b20305
--- /dev/null
+++ b/src/db/localDB.ts
@@ -0,0 +1,148 @@
+import { Note } from '../types';
+
+const DB_NAME = 'nextcloud-notes-db';
+const DB_VERSION = 1;
+const NOTES_STORE = 'notes';
+const SYNC_QUEUE_STORE = 'syncQueue';
+
+export interface SyncOperation {
+  id: string;
+  type: 'create' | 'update' | 'delete';
+  noteId: number | string;
+  note?: Note;
+  timestamp: number;
+  retryCount: number;
+}
+
+class LocalDB {
+  private db: IDBDatabase | null = null;
+
+  async init(): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const request = indexedDB.open(DB_NAME, DB_VERSION);
+
+      request.onerror = () => reject(request.error);
+      request.onsuccess = () => {
+        this.db = request.result;
+        resolve();
+      };
+
+      request.onupgradeneeded = (event) => {
+        const db = (event.target as IDBOpenDBRequest).result;
+
+        if (!db.objectStoreNames.contains(NOTES_STORE)) {
+          const notesStore = db.createObjectStore(NOTES_STORE, { keyPath: 'id' });
+          notesStore.createIndex('modified', 'modified', { unique: false });
+          notesStore.createIndex('category', 'category', { unique: false });
+        }
+
+        if (!db.objectStoreNames.contains(SYNC_QUEUE_STORE)) {
+          db.createObjectStore(SYNC_QUEUE_STORE, { keyPath: 'id' });
+        }
+      };
+    });
+  }
+
+  private getStore(storeName: string, mode: IDBTransactionMode = 'readonly'): IDBObjectStore {
+    if (!this.db) throw new Error('Database not initialized');
+    const transaction = this.db.transaction(storeName, mode);
+    return transaction.objectStore(storeName);
+  }
+
+  // Notes operations
+  async getAllNotes(): Promise<Note[]> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE);
+      const request = store.getAll();
+      request.onsuccess = () => resolve(request.result);
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async getNote(id: number): Promise<Note | undefined> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE);
+      const request = store.get(id);
+      request.onsuccess = () => resolve(request.result);
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async saveNote(note: Note): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE, 'readwrite');
+      const request = store.put(note);
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async saveNotes(notes: Note[]): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE, 'readwrite');
+      const transaction = store.transaction;
+      
+      notes.forEach(note => store.put(note));
+      
+      transaction.oncomplete = () => resolve();
+      transaction.onerror = () => reject(transaction.error);
+    });
+  }
+
+  async deleteNote(id: number): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE, 'readwrite');
+      const request = store.delete(id);
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async clearNotes(): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(NOTES_STORE, 'readwrite');
+      const request = store.clear();
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  // Sync queue operations
+  async addToSyncQueue(operation: SyncOperation): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(SYNC_QUEUE_STORE, 'readwrite');
+      const request = store.put(operation);
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async getSyncQueue(): Promise<SyncOperation[]> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(SYNC_QUEUE_STORE);
+      const request = store.getAll();
+      request.onsuccess = () => resolve(request.result);
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async removeFromSyncQueue(id: string): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(SYNC_QUEUE_STORE, 'readwrite');
+      const request = store.delete(id);
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+
+  async clearSyncQueue(): Promise<void> {
+    return new Promise((resolve, reject) => {
+      const store = this.getStore(SYNC_QUEUE_STORE, 'readwrite');
+      const request = store.clear();
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error);
+    });
+  }
+}
+
+export const localDB = new LocalDB();
diff --git a/src/hooks/useOnlineStatus.ts b/src/hooks/useOnlineStatus.ts
new file mode 100644
index 0000000..d9e81d3
--- /dev/null
+++ b/src/hooks/useOnlineStatus.ts
@@ -0,0 +1,20 @@
+import { useState, useEffect } from 'react';
+
+export function useOnlineStatus() {
+  const [isOnline, setIsOnline] = useState(navigator.onLine);
+
+  useEffect(() => {
+    const handleOnline = () => setIsOnline(true);
+    const handleOffline = () => setIsOnline(false);
+
+    window.addEventListener('online', handleOnline);
+    window.addEventListener('offline', handleOffline);
+
+    return () => {
+      window.removeEventListener('online', handleOnline);
+      window.removeEventListener('offline', handleOffline);
+    };
+  }, []);
+
+  return isOnline;
+}
diff --git a/src/services/syncManager.ts b/src/services/syncManager.ts
new file mode 100644
index 0000000..502d6e7
--- /dev/null
+++ b/src/services/syncManager.ts
@@ -0,0 +1,273 @@
+import { Note } from '../types';
+import { NextcloudAPI } from '../api/nextcloud';
+import { localDB, SyncOperation } from '../db/localDB';
+
+export type SyncStatus = 'idle' | 'syncing' | 'error' | 'offline';
+
+export class SyncManager {
+  private api: NextcloudAPI | null = null;
+  private isOnline: boolean = navigator.onLine;
+  private syncInProgress: boolean = false;
+  private statusCallback: ((status: SyncStatus, pendingCount: number) => void) | null = null;
+
+  constructor() {
+    window.addEventListener('online', () => {
+      this.isOnline = true;
+      this.notifyStatus('idle', 0);
+      this.processSyncQueue();
+    });
+
+    window.addEventListener('offline', () => {
+      this.isOnline = false;
+      this.notifyStatus('offline', 0);
+    });
+  }
+
+  setAPI(api: NextcloudAPI | null) {
+    this.api = api;
+  }
+
+  setStatusCallback(callback: (status: SyncStatus, pendingCount: number) => void) {
+    this.statusCallback = callback;
+  }
+
+  private notifyStatus(status: SyncStatus, pendingCount: number) {
+    if (this.statusCallback) {
+      this.statusCallback(status, pendingCount);
+    }
+  }
+
+  private async getPendingCount(): Promise<number> {
+    const queue = await localDB.getSyncQueue();
+    return queue.length;
+  }
+
+  // Load notes from local DB first, then sync with server
+  async loadNotes(): Promise<Note[]> {
+    const localNotes = await localDB.getAllNotes();
+    
+    if (this.isOnline && this.api) {
+      try {
+        await this.syncWithServer();
+        return await localDB.getAllNotes();
+      } catch (error) {
+        console.error('Failed to sync with server, using local data:', error);
+        return localNotes;
+      }
+    }
+    
+    return localNotes;
+  }
+
+  // Sync with server: fetch remote notes and merge with local
+  async syncWithServer(): Promise<void> {
+    if (!this.api || !this.isOnline || this.syncInProgress) return;
+
+    this.syncInProgress = true;
+    this.notifyStatus('syncing', await this.getPendingCount());
+
+    try {
+      // First, process any pending operations
+      await this.processSyncQueue();
+
+      // Then fetch latest from server
+      const serverNotes = await this.api.fetchNotes();
+      const localNotes = await localDB.getAllNotes();
+
+      // Merge strategy: server wins for conflicts (last-write-wins based on modified timestamp)
+      const mergedNotes = this.mergeNotes(localNotes, serverNotes);
+      
+      // Save merged notes to local DB
+      await localDB.clearNotes();
+      await localDB.saveNotes(mergedNotes);
+
+      this.notifyStatus('idle', 0);
+    } catch (error) {
+      console.error('Sync failed:', error);
+      this.notifyStatus('error', await this.getPendingCount());
+      throw error;
+    } finally {
+      this.syncInProgress = false;
+    }
+  }
+
+  private mergeNotes(localNotes: Note[], serverNotes: Note[]): Note[] {
+    const serverMap = new Map(serverNotes.map(n => [n.id, n]));
+    const merged: Note[] = [];
+
+    // Add all server notes (they are the source of truth)
+    serverNotes.forEach(serverNote => {
+      merged.push(serverNote);
+    });
+
+    // Add local-only notes (not yet synced, likely have temporary IDs)
+    localNotes.forEach(localNote => {
+      if (!serverMap.has(localNote.id)) {
+        merged.push(localNote);
+      }
+    });
+
+    return merged;
+  }
+
+  // Create note (offline-first)
+  async createNote(title: string, content: string, category: string): Promise<Note> {
+    // Create temporary note with negative ID for offline mode
+    const tempNote: Note = {
+      id: -Date.now(), // Temporary negative ID
+      etag: '',
+      readonly: false,
+      content,
+      title,
+      category,
+      favorite: false,
+      modified: Math.floor(Date.now() / 1000),
+    };
+
+    // Save to local DB immediately
+    await localDB.saveNote(tempNote);
+
+    // Queue for sync
+    const operation: SyncOperation = {
+      id: `create-${tempNote.id}-${Date.now()}`,
+      type: 'create',
+      noteId: tempNote.id,
+      note: tempNote,
+      timestamp: Date.now(),
+      retryCount: 0,
+    };
+    await localDB.addToSyncQueue(operation);
+
+    // Try to sync immediately if online
+    if (this.isOnline && this.api) {
+      this.processSyncQueue().catch(console.error);
+    } else {
+      this.notifyStatus('offline', await this.getPendingCount());
+    }
+
+    return tempNote;
+  }
+
+  // Update note (offline-first)
+  async updateNote(note: Note): Promise<Note> {
+    // Update local DB immediately
+    await localDB.saveNote(note);
+
+    // Queue for sync
+    const operation: SyncOperation = {
+      id: `update-${note.id}-${Date.now()}`,
+      type: 'update',
+      noteId: note.id,
+      note,
+      timestamp: Date.now(),
+      retryCount: 0,
+    };
+    await localDB.addToSyncQueue(operation);
+
+    // Try to sync immediately if online
+    if (this.isOnline && this.api) {
+      this.processSyncQueue().catch(console.error);
+    } else {
+      this.notifyStatus('offline', await this.getPendingCount());
+    }
+
+    return note;
+  }
+
+  // Delete note (offline-first)
+  async deleteNote(id: number): Promise<void> {
+    // Delete from local DB immediately
+    await localDB.deleteNote(id);
+
+    // Queue for sync (only if it's a real server ID, not temporary)
+    if (id > 0) {
+      const operation: SyncOperation = {
+        id: `delete-${id}-${Date.now()}`,
+        type: 'delete',
+        noteId: id,
+        timestamp: Date.now(),
+        retryCount: 0,
+      };
+      await localDB.addToSyncQueue(operation);
+
+      // Try to sync immediately if online
+      if (this.isOnline && this.api) {
+        this.processSyncQueue().catch(console.error);
+      } else {
+        this.notifyStatus('offline', await this.getPendingCount());
+      }
+    }
+  }
+
+  // Process sync queue
+  async processSyncQueue(): Promise<void> {
+    if (!this.api || !this.isOnline || this.syncInProgress) return;
+
+    const queue = await localDB.getSyncQueue();
+    if (queue.length === 0) return;
+
+    this.syncInProgress = true;
+    this.notifyStatus('syncing', queue.length);
+
+    for (const operation of queue) {
+      try {
+        await this.processOperation(operation);
+        await localDB.removeFromSyncQueue(operation.id);
+      } catch (error) {
+        console.error(`Failed to process operation ${operation.id}:`, error);
+        
+        // Increment retry count
+        operation.retryCount++;
+        if (operation.retryCount > 5) {
+          console.error(`Operation ${operation.id} failed after 5 retries, removing from queue`);
+          await localDB.removeFromSyncQueue(operation.id);
+        } else {
+          await localDB.addToSyncQueue(operation);
+        }
+      }
+    }
+
+    this.syncInProgress = false;
+    const remainingCount = await this.getPendingCount();
+    this.notifyStatus(remainingCount > 0 ? 'error' : 'idle', remainingCount);
+  }
+
+  private async processOperation(operation: SyncOperation): Promise<void> {
+    if (!this.api) throw new Error('API not initialized');
+
+    switch (operation.type) {
+      case 'create':
+        if (operation.note) {
+          const serverNote = await this.api.createNote(
+            operation.note.title,
+            operation.note.content,
+            operation.note.category
+          );
+          
+          // Replace temporary note with server note
+          await localDB.deleteNote(operation.note.id);
+          await localDB.saveNote(serverNote);
+        }
+        break;
+
+      case 'update':
+        if (operation.note && operation.note.id > 0) {
+          const serverNote = await this.api.updateNote(operation.note);
+          await localDB.saveNote(serverNote);
+        }
+        break;
+
+      case 'delete':
+        if (typeof operation.noteId === 'number' && operation.noteId > 0) {
+          await this.api.deleteNote(operation.noteId);
+        }
+        break;
+    }
+  }
+
+  getOnlineStatus(): boolean {
+    return this.isOnline;
+  }
+}
+
+export const syncManager = new SyncManager();