diff --git a/backend/main.py b/backend/main.py
index fe27243..3f3a50c 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -3,7 +3,7 @@ NoteDiscovery - Self-Hosted Markdown Knowledge Base
 Main FastAPI application
 """
 
-from fastapi import FastAPI, HTTPException, UploadFile, File, Request, Form, Depends, APIRouter
+from fastapi import FastAPI, HTTPException, UploadFile, File, Request, Form, Depends, APIRouter, Response
 from fastapi.staticfiles import StaticFiles
 from fastapi.responses import HTMLResponse, JSONResponse, FileResponse, RedirectResponse
 from fastapi.middleware.cors import CORSMiddleware
@@ -171,6 +171,21 @@ plugin_manager.run_hook('on_app_startup')
 static_path = Path(__file__).parent.parent / "frontend"
 app.mount("/static", StaticFiles(directory=static_path), name="static")
 
+# PWA Service Worker - must be served from root for proper scope
+@app.get("/sw.js")
+@limiter.limit("30/minute")
+async def service_worker(request: Request):
+    """Serve the PWA service worker from root path for proper scope.
+    Injects the app version from VERSION file for cache invalidation."""
+    sw_path = static_path / "sw.js"
+    if sw_path.exists():
+        async with aiofiles.open(sw_path, 'r', encoding='utf-8') as f:
+            content = await f.read()
+        # Inject app version into cache name
+        content = content.replace('__APP_VERSION__', version)
+        return Response(content=content, media_type="application/javascript")
+    raise HTTPException(status_code=404, detail="Service worker not found")
+
 
 # ============================================================================
 # Custom Exception Handlers
diff --git a/frontend/app.js b/frontend/app.js
index 8644aa5..d01e9e2 100644
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -875,6 +875,15 @@ function noteApp() {
                 if (this.showGraph) {
                     setTimeout(() => this.initGraph(), 300);
                 }
+                
+                // Update PWA theme-color meta tag to match current theme
+                const themeColorMeta = document.querySelector('meta[name="theme-color"]');
+                if (themeColorMeta) {
+                    // Get the accent color from CSS variables
+                    const accentColor = getComputedStyle(document.documentElement)
+                        .getPropertyValue('--accent-primary').trim() || '#667eea';
+                    themeColorMeta.setAttribute('content', accentColor);
+                }
             } catch (error) {
                 console.error('Failed to load theme:', error);
             }
diff --git a/frontend/index.html b/frontend/index.html
index 44aa8c5..8548888 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -11,6 +11,20 @@
     <link rel="icon" type="image/png" sizes="16x16" href="/static/favicon.svg">
     <link rel="apple-touch-icon" href="/static/logo.svg">
     
+    <!-- PWA Manifest -->
+    <link rel="manifest" href="/static/manifest.json">
+    
+    <!-- PWA Meta Tags -->
+    <meta name="application-name" content="NoteDiscovery">
+    <meta name="apple-mobile-web-app-capable" content="yes">
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+    <meta name="apple-mobile-web-app-title" content="NoteDiscovery">
+    <meta name="mobile-web-app-capable" content="yes">
+    <!-- Theme color: initial value, updated dynamically by app.js when theme changes -->
+    <meta name="theme-color" content="#667eea">
+    <meta name="msapplication-TileColor" content="#667eea">
+    <meta name="msapplication-tap-highlight" content="no">
+    
     <!-- Tailwind CSS from CDN (v3.4.17) -->
     <script src="https://cdn.tailwindcss.com/3.4.17"></script>
     
@@ -2816,6 +2830,21 @@
     </nav>
     
     <script src="/static/app.js"></script>
+    
+    <!-- PWA Service Worker Registration -->
+    <script>
+        if ('serviceWorker' in navigator) {
+            window.addEventListener('load', () => {
+                navigator.serviceWorker.register('/sw.js')
+                    .then((registration) => {
+                        console.log('SW registered:', registration.scope);
+                    })
+                    .catch((error) => {
+                        console.log('SW registration failed:', error);
+                    });
+            });
+        }
+    </script>
 </body>
 </html>
 
diff --git a/frontend/login.html b/frontend/login.html
index 6ae4e0c..8e0706e 100644
--- a/frontend/login.html
+++ b/frontend/login.html
@@ -6,6 +6,13 @@
     <title>Login - NoteDiscovery</title>
     <link rel="icon" type="image/svg+xml" href="/static/favicon.svg">
     
+    <!-- PWA Manifest -->
+    <link rel="manifest" href="/static/manifest.json">
+    <meta name="theme-color" content="#667eea">
+    <meta name="apple-mobile-web-app-capable" content="yes">
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+    <meta name="apple-mobile-web-app-title" content="NoteDiscovery">
+    
     <!-- Preload translations (same approach as index.html) -->
     <script>
         (function() {
diff --git a/frontend/manifest.json b/frontend/manifest.json
new file mode 100644
index 0000000..b7a0666
--- /dev/null
+++ b/frontend/manifest.json
@@ -0,0 +1,33 @@
+{
+  "name": "NoteDiscovery",
+  "short_name": "Notes",
+  "description": "A beautiful, self-hosted markdown notes application",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#0f172a",
+  "theme_color": "#667eea",
+  "orientation": "any",
+  "scope": "/",
+  "icons": [
+    {
+      "src": "/static/logo.svg",
+      "sizes": "any",
+      "type": "image/svg+xml",
+      "purpose": "any"
+    },
+    {
+      "src": "/static/logo.svg",
+      "sizes": "192x192",
+      "type": "image/svg+xml",
+      "purpose": "any maskable"
+    },
+    {
+      "src": "/static/logo.svg",
+      "sizes": "512x512",
+      "type": "image/svg+xml",
+      "purpose": "any maskable"
+    }
+  ],
+  "categories": ["productivity", "utilities"]
+}
+
diff --git a/frontend/sw.js b/frontend/sw.js
new file mode 100644
index 0000000..9deac64
--- /dev/null
+++ b/frontend/sw.js
@@ -0,0 +1,67 @@
+// NoteDiscovery Service Worker
+// Minimal service worker for PWA install support
+
+// Cache version - automatically uses app version from VERSION file
+// Cache is invalidated when app version changes (e.g., 0.10.4 -> 0.10.5)
+// This forces users to download fresh files when you release a new version.
+const CACHE_NAME = 'notediscovery-__APP_VERSION__';
+
+// Assets to cache for faster repeat visits
+const PRECACHE_ASSETS = [
+  '/static/logo.svg',
+  '/static/favicon.svg',
+  '/static/app.js'
+];
+
+// Install event - cache essential assets
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then((cache) => cache.addAll(PRECACHE_ASSETS))
+      .then(() => self.skipWaiting())
+  );
+});
+
+// Activate event - clean up old caches
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames
+          .filter((name) => name !== CACHE_NAME)
+          .map((name) => caches.delete(name))
+      );
+    }).then(() => self.clients.claim())
+  );
+});
+
+// Fetch event - network first, fallback to cache for assets
+self.addEventListener('fetch', (event) => {
+  const url = new URL(event.request.url);
+  
+  // Only handle same-origin requests
+  if (url.origin !== location.origin) {
+    return;
+  }
+  
+  // For API calls, always go to network
+  if (url.pathname.startsWith('/api/')) {
+    return;
+  }
+  
+  // For static assets, try cache first then network
+  if (url.pathname.startsWith('/static/')) {
+    event.respondWith(
+      caches.match(event.request)
+        .then((cached) => cached || fetch(event.request))
+    );
+    return;
+  }
+  
+  // For everything else, network first
+  event.respondWith(
+    fetch(event.request)
+      .catch(() => caches.match(event.request))
+  );
+});
+