diff --git a/mathsquiz/calculusquiz.html b/mathsquiz/calculusquiz.html
index 90df9cc..0e9671e 100644
--- a/mathsquiz/calculusquiz.html
+++ b/mathsquiz/calculusquiz.html
@@ -51,10 +51,22 @@ <h2>🎉 Quiz Completed!</h2>
     </div>
   </div>
 
+  <script src="../offlineSync.js"></script>
   <script src="../quizProgress.js"></script>
   <script src="../badges.js"></script>
   <script src="calculusquiz.js"></script>
   <script src="../quizAssignmentHelper.js"></script>
+
+  <script>
+    (function () {
+      if (!('serviceWorker' in navigator)) return;
+      window.addEventListener('load', function () {
+        navigator.serviceWorker.register('/sw.js').catch(function (err) {
+          console.warn('LearnSphere: Service Worker registration failed:', err);
+        });
+      });
+    })();
+  </script>
 </body>
 
 </html>
\ No newline at end of file
diff --git a/mathsquiz/geometryquiz.html b/mathsquiz/geometryquiz.html
index d145636..19e4865 100644
--- a/mathsquiz/geometryquiz.html
+++ b/mathsquiz/geometryquiz.html
@@ -51,10 +51,22 @@ <h2>🎉 Quiz Completed!</h2>
     </div>
   </div>
 
+  <script src="../offlineSync.js"></script>
   <script src="../quizProgress.js"></script>
   <script src="../badges.js"></script>
   <script src="geometryquiz.js"></script>
   <script src="../quizAssignmentHelper.js"></script>
+
+  <script>
+    (function () {
+      if (!('serviceWorker' in navigator)) return;
+      window.addEventListener('load', function () {
+        navigator.serviceWorker.register('/sw.js').catch(function (err) {
+          console.warn('LearnSphere: Service Worker registration failed:', err);
+        });
+      });
+    })();
+  </script>
 </body>
 
 </html>
\ No newline at end of file
diff --git a/mathsquiz/probabilityquiz.html b/mathsquiz/probabilityquiz.html
index 4d2bcbf..b503617 100644
--- a/mathsquiz/probabilityquiz.html
+++ b/mathsquiz/probabilityquiz.html
@@ -51,10 +51,22 @@ <h2>🎉 Quiz Completed!</h2>
     </div>
   </div>
 
+  <script src="../offlineSync.js"></script>
   <script src="../quizProgress.js"></script>
   <script src="../badges.js"></script>
   <script src="probabilityquiz.js"></script>
   <script src="../quizAssignmentHelper.js"></script>
+
+  <script>
+    (function () {
+      if (!('serviceWorker' in navigator)) return;
+      window.addEventListener('load', function () {
+        navigator.serviceWorker.register('/sw.js').catch(function (err) {
+          console.warn('LearnSphere: Service Worker registration failed:', err);
+        });
+      });
+    })();
+  </script>
 </body>
 
 </html>
\ No newline at end of file
diff --git a/mathsquiz/vectorquiz.html b/mathsquiz/vectorquiz.html
index 9eb198d..126911c 100644
--- a/mathsquiz/vectorquiz.html
+++ b/mathsquiz/vectorquiz.html
@@ -51,10 +51,22 @@ <h2>🎉 Quiz Completed!</h2>
     </div>
   </div>
 
+  <script src="../offlineSync.js"></script>
   <script src="../quizProgress.js"></script>
   <script src="../badges.js"></script>
   <script src="vectorquiz.js"></script>
   <script src="../quizAssignmentHelper.js"></script>
+
+  <script>
+    (function () {
+      if (!('serviceWorker' in navigator)) return;
+      window.addEventListener('load', function () {
+        navigator.serviceWorker.register('/sw.js').catch(function (err) {
+          console.warn('LearnSphere: Service Worker registration failed:', err);
+        });
+      });
+    })();
+  </script>
 </body>
 
 </html>
\ No newline at end of file
diff --git a/offlineSync.js b/offlineSync.js
new file mode 100644
index 0000000..a98f4d5
--- /dev/null
+++ b/offlineSync.js
@@ -0,0 +1,366 @@
+/**
+ * offlineSync.js — LearnSphere Offline Sync Manager
+ *
+ * Queues quiz progress updates when offline and flushes them on reconnect.
+ * Currently the app is localStorage-only; the queue is structured so a future
+ * backend can POST each entry to /api/sync-progress without changes.
+ *
+ * Usage: Include this script BEFORE quizProgress.js on quiz pages.
+ *
+ * Public API (via window.offlineSync):
+ *   queueProgressUpdate(type, payload)  — add an item to the offline queue
+ *   flushQueue()                        — replay queued items and clear
+ *   getQueueLength()                    — pending items count
+ *   isOnline()                          — navigator.onLine wrapper
+ */
+
+(function () {
+  "use strict";
+
+  const QUEUE_KEY = "learnsphere_offline_queue_v1";
+  const DEDUP_WINDOW_MS = 2000; // ignore duplicate entries within 2 s
+
+  // ── Queue Persistence ─────────────────────────────────────────────────────
+
+  function _loadQueue() {
+    try {
+      const raw = localStorage.getItem(QUEUE_KEY);
+      if (!raw) return [];
+      const parsed = JSON.parse(raw);
+      return Array.isArray(parsed) ? parsed : [];
+    } catch {
+      return [];
+    }
+  }
+
+  function _saveQueue(queue) {
+    try {
+      localStorage.setItem(QUEUE_KEY, JSON.stringify(queue));
+    } catch (e) {
+      console.warn("LearnSphere: Could not persist offline queue.", e);
+    }
+  }
+
+  // ── Public API ────────────────────────────────────────────────────────────
+
+  /**
+   * Queue a progress update for future sync.
+   * @param {"quiz_attempt"|"retry_attempt"} type
+   * @param {Object} payload — arguments originally passed to recordAttempt / recordRetryAttempt
+   */
+  function queueProgressUpdate(type, payload) {
+    const queue = _loadQueue();
+    const now = Date.now();
+
+    // Basic dedup: skip if an identical-looking entry was queued very recently
+    const isDuplicate = queue.some(
+      (item) =>
+        item.type === type &&
+        item.payload &&
+        item.payload.topicId === payload.topicId &&
+        item.payload.quizId === payload.quizId &&
+        Math.abs(now - item.queuedAt) < DEDUP_WINDOW_MS
+    );
+    if (isDuplicate) return;
+
+    queue.push({
+      id: _uid(),
+      type,
+      payload,
+      queuedAt: now,
+      synced: false,
+    });
+
+    // Keep queue bounded (max 200 entries)
+    if (queue.length > 200) {
+      queue.splice(0, queue.length - 200);
+    }
+
+    _saveQueue(queue);
+    _dispatchQueueChange(queue.length);
+  }
+
+  /**
+   * Flush all queued progress updates.
+   * Since the app currently uses localStorage only, flushing means marking
+   * entries as synced (the data is already saved locally by quizProgress.js).
+   * When a backend is added, each entry can be POSTed here before marking synced.
+   */
+  function flushQueue() {
+    const queue = _loadQueue();
+    if (queue.length === 0) return;
+
+    let flushedCount = 0;
+
+    for (const item of queue) {
+      if (item.synced) continue;
+
+      try {
+        // Future: POST to /api/sync-progress
+        // For now, the data is already in localStorage via quizProgress.js.
+        // We just mark the entry as synced.
+        item.synced = true;
+        flushedCount++;
+      } catch (e) {
+        console.warn("LearnSphere: Failed to sync queued item:", item.id, e);
+        // Leave unsynced so it retries next time
+      }
+    }
+
+    // Remove synced items
+    const remaining = queue.filter((item) => !item.synced);
+    _saveQueue(remaining);
+
+    if (flushedCount > 0) {
+      console.info(`LearnSphere: Synced ${flushedCount} queued progress update(s).`);
+      _dispatchSyncComplete(flushedCount);
+    }
+
+    _dispatchQueueChange(remaining.length);
+  }
+
+  /** @returns {number} Number of pending (unsynced) items */
+  function getQueueLength() {
+    const queue = _loadQueue();
+    return queue.filter((item) => !item.synced).length;
+  }
+
+  /** @returns {boolean} Current network status */
+  function isOnline() {
+    return navigator.onLine !== false;
+  }
+
+  // ── Internal Helpers ──────────────────────────────────────────────────────
+
+  function _uid() {
+    return Date.now().toString(36) + Math.random().toString(36).slice(2, 8);
+  }
+
+  function _dispatchQueueChange(pendingCount) {
+    try {
+      window.dispatchEvent(
+        new CustomEvent("learnsphere:queue-change", {
+          detail: { pendingCount },
+        })
+      );
+    } catch {
+      // Ignore if CustomEvent is unsupported
+    }
+  }
+
+  function _dispatchSyncComplete(syncedCount) {
+    try {
+      window.dispatchEvent(
+        new CustomEvent("learnsphere:sync-complete", {
+          detail: { syncedCount },
+        })
+      );
+    } catch {
+      // Ignore
+    }
+  }
+
+  // ── Auto-sync on Reconnect ────────────────────────────────────────────────
+
+  function _onOnline() {
+    console.info("LearnSphere: Back online — flushing offline queue.");
+    flushQueue();
+
+    // Request Background Sync if available (for reliability)
+    if ("serviceWorker" in navigator && "SyncManager" in window) {
+      navigator.serviceWorker.ready
+        .then((reg) => reg.sync.register("learnsphere-sync-progress"))
+        .catch(() => {
+          // Background Sync not available; manual flush above covers it
+        });
+    }
+  }
+
+  window.addEventListener("online", _onOnline);
+
+  // Also flush on page load if online and there are queued items
+  function _initFlush() {
+    if (isOnline() && getQueueLength() > 0) {
+      flushQueue();
+    }
+  }
+
+  if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", _initFlush);
+  } else {
+    _initFlush();
+  }
+
+  // ── Offline Status Bar UI Helper ──────────────────────────────────────────
+
+  /**
+   * Injects an offline/online status bar into the quiz page.
+   * Call once on DOMContentLoaded. The bar auto-updates on connectivity changes.
+   */
+  function initOfflineStatusBar() {
+    const container = document.querySelector(".container");
+    if (!container) return;
+
+    // Create status bar element
+    const bar = document.createElement("div");
+    bar.id = "offline-status-bar";
+    bar.setAttribute("role", "status");
+    bar.setAttribute("aria-live", "polite");
+    bar.style.cssText = [
+      "display: none",
+      "padding: 10px 16px",
+      "border-radius: 10px",
+      "margin-bottom: 16px",
+      "font-size: 0.88rem",
+      "font-weight: 600",
+      "font-family: 'Poppins', 'Inter', sans-serif",
+      "transition: all 0.3s ease",
+      "position: relative",
+      "overflow: hidden",
+    ].join(";");
+
+    // Insert as first child of .container
+    container.insertBefore(bar, container.firstChild);
+
+    // Inject animation styles
+    if (!document.getElementById("offline-status-styles")) {
+      const style = document.createElement("style");
+      style.id = "offline-status-styles";
+      style.textContent = `
+        @keyframes offlineSlideDown {
+          from { transform: translateY(-20px); opacity: 0; }
+          to { transform: translateY(0); opacity: 1; }
+        }
+        @keyframes offlinePulse {
+          0%, 100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.3); }
+          50% { box-shadow: 0 0 0 6px rgba(239, 68, 68, 0); }
+        }
+        @keyframes syncPulse {
+          0%, 100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.3); }
+          50% { box-shadow: 0 0 0 6px rgba(34, 197, 94, 0); }
+        }
+        #offline-status-bar.offline-active {
+          display: flex !important;
+          align-items: center;
+          gap: 10px;
+          background: linear-gradient(135deg, rgba(239, 68, 68, 0.15), rgba(239, 68, 68, 0.08));
+          border: 1px solid rgba(239, 68, 68, 0.3);
+          color: #fca5a5;
+          animation: offlineSlideDown 0.3s ease-out, offlinePulse 2s ease-in-out 3;
+        }
+        #offline-status-bar.sync-success {
+          display: flex !important;
+          align-items: center;
+          gap: 10px;
+          background: linear-gradient(135deg, rgba(34, 197, 94, 0.15), rgba(34, 197, 94, 0.08));
+          border: 1px solid rgba(34, 197, 94, 0.3);
+          color: #86efac;
+          animation: offlineSlideDown 0.3s ease-out, syncPulse 1.5s ease-in-out 2;
+        }
+        #offline-status-bar .queue-badge {
+          background: rgba(255, 255, 255, 0.15);
+          padding: 2px 8px;
+          border-radius: 12px;
+          font-size: 0.78rem;
+          margin-left: auto;
+        }
+        #offline-status-bar .dismiss-btn {
+          background: none;
+          border: none;
+          color: inherit;
+          cursor: pointer;
+          font-size: 1.1rem;
+          padding: 0 4px;
+          margin-left: 8px;
+          opacity: 0.7;
+          transition: opacity 0.2s;
+        }
+        #offline-status-bar .dismiss-btn:hover {
+          opacity: 1;
+        }
+      `;
+      document.head.appendChild(style);
+    }
+
+    let syncDismissTimer = null;
+
+    function updateBar() {
+      const online = isOnline();
+      const pending = getQueueLength();
+
+      if (!online) {
+        // Offline state
+        bar.className = "offline-active";
+        bar.innerHTML = `
+          <span>📴 You're offline — your quiz works normally. Progress is saved locally.</span>
+          ${pending > 0 ? `<span class="queue-badge">${pending} pending</span>` : ""}
+        `;
+        if (syncDismissTimer) {
+          clearTimeout(syncDismissTimer);
+          syncDismissTimer = null;
+        }
+      } else if (bar.classList.contains("offline-active")) {
+        // Just came back online
+        bar.className = "sync-success";
+        bar.innerHTML = `
+          <span>✅ Back online — progress synced!</span>
+          <button class="dismiss-btn" aria-label="Dismiss" title="Dismiss">✕</button>
+        `;
+        bar.querySelector(".dismiss-btn").addEventListener("click", () => {
+          bar.className = "";
+          bar.style.display = "none";
+        });
+        // Auto-dismiss after 5 seconds
+        syncDismissTimer = setTimeout(() => {
+          bar.className = "";
+          bar.style.display = "none";
+        }, 5000);
+      }
+    }
+
+    // Wire up events
+    window.addEventListener("online", updateBar);
+    window.addEventListener("offline", updateBar);
+    window.addEventListener("learnsphere:sync-complete", () => {
+      if (isOnline()) {
+        bar.className = "sync-success";
+        bar.innerHTML = `
+          <span>✅ Back online — progress synced!</span>
+          <button class="dismiss-btn" aria-label="Dismiss" title="Dismiss">✕</button>
+        `;
+        bar.querySelector(".dismiss-btn").addEventListener("click", () => {
+          bar.className = "";
+          bar.style.display = "none";
+        });
+        if (syncDismissTimer) clearTimeout(syncDismissTimer);
+        syncDismissTimer = setTimeout(() => {
+          bar.className = "";
+          bar.style.display = "none";
+        }, 5000);
+      }
+    });
+    window.addEventListener("learnsphere:queue-change", (e) => {
+      if (!isOnline()) updateBar();
+    });
+
+    // Initial check
+    updateBar();
+  }
+
+  // Auto-init the status bar when DOM is ready
+  if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", initOfflineStatusBar);
+  } else {
+    initOfflineStatusBar();
+  }
+
+  // ── Export ─────────────────────────────────────────────────────────────────
+
+  window.offlineSync = {
+    queueProgressUpdate,
+    flushQueue,
+    getQueueLength,
+    isOnline,
+    initOfflineStatusBar,
+  };
+})();
diff --git a/quiz/motionquiz.html b/quiz/motionquiz.html
index 5978972..d3ab2f6 100644
--- a/quiz/motionquiz.html
+++ b/quiz/motionquiz.html
@@ -62,7 +62,7 @@ <h2 id="result-title" tabindex="-1">🎉 Quiz Completed!</h2>
         </section>
     </div>
 
-    <script src="../accessibility.js"></script>
+    <script src="../offlineSync.js"></script>
     <script src="../quizProgress.js"></script>
     <script src="../badges.js"></script>
     <script src="adaptiveQuiz.js"></script>
diff --git a/quiz/nlmquiz.html b/quiz/nlmquiz.html
index c23a94e..c7deaa8 100644
--- a/quiz/nlmquiz.html
+++ b/quiz/nlmquiz.html
@@ -64,7 +64,7 @@ <h2 id="result-title" tabindex="-1">🎉 Quiz Completed!</h2>
         </section>
     </div>
 
-    <script src="../accessibility.js"></script>
+    <script src="../offlineSync.js"></script>
     <script src="../quizProgress.js"></script>
     <script src="../badges.js"></script>
     <script src="adaptiveQuiz.js"></script>
diff --git a/quiz/projectilequiz.html b/quiz/projectilequiz.html
index 5db9b12..0074cee 100644
--- a/quiz/projectilequiz.html
+++ b/quiz/projectilequiz.html
@@ -67,6 +67,7 @@ <h2 tabindex="-1" id="result-heading">🎉 Quiz Completed!</h2>
 
     </div>
 
+    <script src="../offlineSync.js"></script>
     <script src="../quizProgress.js"></script>
 <script src="../accessibility.js"></script>
     <script src="../badges.js"></script>
@@ -74,6 +75,16 @@ <h2 tabindex="-1" id="result-heading">🎉 Quiz Completed!</h2>
     <script src="projectilequiz.js"></script>
     <script src="../quizAssignmentHelper.js"></script>
 
+    <script>
+      (function () {
+        if (!('serviceWorker' in navigator)) return;
+        window.addEventListener('load', function () {
+          navigator.serviceWorker.register('/sw.js').catch(function (err) {
+            console.warn('LearnSphere: Service Worker registration failed:', err);
+          });
+        });
+      })();
+    </script>
 </body>
 
 </html>
\ No newline at end of file
diff --git a/quiz/rayquiz.html b/quiz/rayquiz.html
index 29752b8..f6ce134 100644
--- a/quiz/rayquiz.html
+++ b/quiz/rayquiz.html
@@ -67,12 +67,24 @@ <h2 tabindex="-1" id="result-heading">🎉 Quiz Completed!</h2>
         </div>
     </div>
 
+    <script src="../offlineSync.js"></script>
     <script src="../quizProgress.js"></script>
 <script src="../accessibility.js"></script>
     <script src="../badges.js"></script>
     <script src="adaptiveQuiz.js"></script>
     <script src="rayquiz.js"></script>
     <script src="../quizAssignmentHelper.js"></script>
+
+    <script>
+      (function () {
+        if (!('serviceWorker' in navigator)) return;
+        window.addEventListener('load', function () {
+          navigator.serviceWorker.register('/sw.js').catch(function (err) {
+            console.warn('LearnSphere: Service Worker registration failed:', err);
+          });
+        });
+      })();
+    </script>
 </body>
 
 </html>
diff --git a/quizProgress.js b/quizProgress.js
index 3701f2a..77a8908 100644
--- a/quizProgress.js
+++ b/quizProgress.js
@@ -367,6 +367,22 @@ function recordAttempt({ topicId, score, totalQuestions, correctCount, timeTaken
   // Update unified streak & daily goal state
   _updateUnifiedStreakAndGoal("quiz", 1);
 
+  // Queue for future backend sync when offline
+  if (window.offlineSync && typeof window.offlineSync.queueProgressUpdate === "function") {
+    if (!window.offlineSync.isOnline()) {
+      window.offlineSync.queueProgressUpdate("quiz_attempt", {
+        topicId,
+        score: got,
+        totalQuestions: total,
+        correctCount: correct,
+        timeTakenMs: timeMs,
+        quizId,
+        finishedAt: now,
+        practiceDate: today,
+      });
+    }
+  }
+
   return state;
 }
 
@@ -682,6 +698,8 @@ window.quizProgress = {
   getQuestionWeaknessWeight,
   recordRetryAttempt,
   getAttemptsHistory,
+  /** @returns {Object|null} offlineSync reference */
+  get offlineSync() { return window.offlineSync || null; },
 };
 
 
@@ -715,7 +733,23 @@ function recordRetryAttempt({ topicId, results }) {
   });
 
   _saveState(state);
-}
 
+  // Queue for future backend sync when offline
+  if (window.offlineSync && typeof window.offlineSync.queueProgressUpdate === "function") {
+    if (!window.offlineSync.isOnline()) {
+      window.offlineSync.queueProgressUpdate("retry_attempt", { topicId, results });
+    }
+  }
+}
 
+// Listen for Background Sync flush messages from service worker
+if ("serviceWorker" in navigator) {
+  navigator.serviceWorker.addEventListener("message", (event) => {
+    if (event.data && event.data.action === "do-flush-offline-queue") {
+      if (window.offlineSync && typeof window.offlineSync.flushQueue === "function") {
+        window.offlineSync.flushQueue();
+      }
+    }
+  });
+}
 
diff --git a/sw.js b/sw.js
index 8ea9bbe..f639c86 100644
--- a/sw.js
+++ b/sw.js
@@ -4,7 +4,7 @@
  */
 
 // Increment this value to invalidate older caches
-const CACHE_VERSION = "v2";
+const CACHE_VERSION = "v3";
 const CACHE_NAME = `learnsphere-static-${CACHE_VERSION}`;
 
 // For runtime image caching
@@ -42,6 +42,7 @@ const APP_SHELL_URLS = [
   "/chemistryquiz/equilibriumquiz.js",
   "/chemistryquiz/thermoquiz.js",
   "/quizAssignmentHelper.js",
+  "/offlineSync.js",
 
   // Quizzes styles
   "/quiz/motionquiz.css",
@@ -84,6 +85,14 @@ const APP_SHELL_URLS = [
   "/progress.js",
   "/review.js",
   "/quizProgress.js",
+  "/badges.js",
+  "/badges.css",
+  "/exportProgress.js",
+  "/dashboardProgress.js",
+
+  // Data
+  "/quiz/bank/physics-motion.json",
+  "/manifest.json",
 
   // Images
   "/student.png",
@@ -120,9 +129,10 @@ self.addEventListener("activate", (event) => {
     (async () => {
       // Remove old caches
       const keys = await caches.keys();
+      const keepCaches = new Set([CACHE_NAME, RUNTIME_IMAGE_CACHE_NAME]);
       await Promise.all(
         keys.map((k) => {
-          if (k !== CACHE_NAME) return caches.delete(k);
+          if (!keepCaches.has(k)) return caches.delete(k);
         })
       );
       self.clients.claim();
@@ -310,7 +320,13 @@ self.addEventListener("message", (event) => {
           "/sub/maths.html",
           "/sub/physics.html",
           "/sub/chemistry.html",
-          "/sub/biology.html"
+          "/sub/biology.html",
+
+          // Quiz data
+          "/quiz/bank/physics-motion.json",
+
+          // Offline sync module
+          "/offlineSync.js"
         ];
 
         try {
@@ -331,5 +347,30 @@ self.addEventListener("message", (event) => {
       })()
     );
   }
+
+  // Handle manual sync flush request from clients
+  if (event.data && event.data.action === "flush-offline-queue") {
+    // Notify all clients to flush their offline queues
+    event.waitUntil(
+      self.clients.matchAll().then((clientsList) => {
+        clientsList.forEach((client) => {
+          client.postMessage({ action: "do-flush-offline-queue" });
+        });
+      })
+    );
+  }
+});
+
+// Background Sync: flush offline queue when connectivity returns
+self.addEventListener("sync", (event) => {
+  if (event.tag === "learnsphere-sync-progress") {
+    event.waitUntil(
+      self.clients.matchAll().then((clientsList) => {
+        clientsList.forEach((client) => {
+          client.postMessage({ action: "do-flush-offline-queue" });
+        });
+      })
+    );
+  }
 });