diff --git a/.gitignore b/.gitignore
index 0db4891..1273cab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 *.crx
 node_modules/*
 CLAUDE.md
+.claude/*
diff --git a/content.js b/content.js
index a96d443..c11adb8 100644
--- a/content.js
+++ b/content.js
@@ -1,10 +1,14 @@
-// Clear active filter when page loads (prevents confusion on page refresh)
+// Pull and apply active filter when page loads (prevents confusion on page refresh)
 // This runs only on NotebookLM pages as defined in manifest.json
 if (typeof FilterState !== 'undefined') {
-  FilterState.clearActiveFilter(function () {
-    // After clearing, visually clear any applied filters on the page
-    if (document.readyState === 'loading') {
-      document.addEventListener('DOMContentLoaded', showAllNotebooks);
+  FilterState.getActiveFilter(function (activeFilter) {
+    // apply filter if present
+    if (document.readyState === 'loading' && activeFilter) {
+      document.addEventListener('DOMContentLoaded', () => {
+        filterNotebooks(activeFilter);
+      });
+    } else if (activeFilter) {
+      filterNotebooks(activeFilter);
     } else {
       showAllNotebooks();
     }
diff --git a/filterState.js b/filterState.js
index ada1d01..24b3cf2 100644
--- a/filterState.js
+++ b/filterState.js
@@ -13,17 +13,28 @@ const FilterState = {
       callback(null);
       return;
     }
-
-    // retrieve from local storage
-    chrome.storage.local.get(['activeFilter'], function (localResult) {
+    // Try sync storage first
+    chrome.storage.sync.get(['activeFilter'], function (result) {
       if (chrome.runtime.lastError) {
-        console.error(
-          'Failed to load activeFilter from local storage:',
+        console.warn(
+          'Failed to load activeFilter from sync storage, trying local:',
           chrome.runtime.lastError
         );
-        callback(null);
+
+        // Fall back to local storage
+        chrome.storage.local.get(['activeFilter'], function (localResult) {
+          if (chrome.runtime.lastError) {
+            console.error(
+              'Failed to load activeFilter from local storage:',
+              chrome.runtime.lastError
+            );
+            callback(null);
+          } else {
+            callback(localResult.activeFilter || null);
+          }
+        });
       } else {
-        callback(localResult.activeFilter || null);
+        callback(result.activeFilter || null);
       }
     });
   },
@@ -41,7 +52,17 @@ const FilterState = {
 
     const data = { activeFilter: filter };
 
-    // Save to local storage
+    // Save to sync storage first
+    chrome.storage.sync.set(data, function () {
+      if (chrome.runtime.lastError) {
+        console.warn(
+          'Failed to save activeFilter to sync storage:',
+          chrome.runtime.lastError
+        );
+      }
+    });
+
+    // Also save to local storage as backup
     chrome.storage.local.set(data, function () {
       if (chrome.runtime.lastError) {
         console.error(
@@ -132,8 +153,3 @@ const FilterState = {
     });
   },
 };
-
-// Export for both browser extension and Node.js (testing)
-if (typeof module !== 'undefined' && module.exports) {
-  module.exports = { FilterState };
-}
diff --git a/jsconfig.json b/jsconfig.json
new file mode 100644
index 0000000..f31719d
--- /dev/null
+++ b/jsconfig.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "types": ["chrome"],
+    "checkJs": false,
+    "module": "none",
+    "moduleResolution": "node"
+  },
+  "exclude": ["node_modules"]
+}
diff --git a/package-lock.json b/package-lock.json
index 1ff9ce4..011dbcf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,7 @@
       "name": "notebooklm-filter-extension",
       "version": "1.0.0",
       "devDependencies": {
+        "@types/chrome": "^0.1.24",
         "jest": "^29.7.0",
         "jest-environment-jsdom": "^29.7.0"
       }
@@ -959,6 +960,34 @@
         "@babel/types": "^7.28.2"
       }
     },
+    "node_modules/@types/chrome": {
+      "version": "0.1.24",
+      "resolved": "https://registry.npmjs.org/@types/chrome/-/chrome-0.1.24.tgz",
+      "integrity": "sha512-9iO9HL2bMeGS4C8m6gNFWUyuPE5HEUFk+rGh+7oriUjg+ata4Fc9PoVlu8xvGm7yoo3AmS3J6fAjoFj61NL2rw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/filesystem": "*",
+        "@types/har-format": "*"
+      }
+    },
+    "node_modules/@types/filesystem": {
+      "version": "0.0.36",
+      "resolved": "https://registry.npmjs.org/@types/filesystem/-/filesystem-0.0.36.tgz",
+      "integrity": "sha512-vPDXOZuannb9FZdxgHnqSwAG/jvdGM8Wq+6N4D/d80z+D4HWH+bItqsZaVRQykAn6WEVeEkLm2oQigyHtgb0RA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/filewriter": "*"
+      }
+    },
+    "node_modules/@types/filewriter": {
+      "version": "0.0.33",
+      "resolved": "https://registry.npmjs.org/@types/filewriter/-/filewriter-0.0.33.tgz",
+      "integrity": "sha512-xFU8ZXTw4gd358lb2jw25nxY9QAgqn2+bKKjKOYfNCzN4DKCFetK7sPtrlpg66Ywe3vWY9FNxprZawAh9wfJ3g==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/graceful-fs": {
       "version": "4.1.9",
       "resolved": "https://registry.npmjs.org/@types/graceful-fs/-/graceful-fs-4.1.9.tgz",
@@ -969,6 +998,13 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/har-format": {
+      "version": "1.2.16",
+      "resolved": "https://registry.npmjs.org/@types/har-format/-/har-format-1.2.16.tgz",
+      "integrity": "sha512-fluxdy7ryD3MV6h8pTfTYpy/xQzCFC7m89nOH9y94cNqJ1mDIDPut7MnRHI3F6qRmh/cT2fUjG1MLdCNb4hE9A==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/istanbul-lib-coverage": {
       "version": "2.0.6",
       "resolved": "https://registry.npmjs.org/@types/istanbul-lib-coverage/-/istanbul-lib-coverage-2.0.6.tgz",
diff --git a/package.json b/package.json
index 14fd629..97dcf52 100644
--- a/package.json
+++ b/package.json
@@ -8,12 +8,15 @@
     "test:coverage": "jest --coverage"
   },
   "devDependencies": {
+    "@types/chrome": "^0.1.24",
     "jest": "^29.7.0",
     "jest-environment-jsdom": "^29.7.0"
   },
   "jest": {
     "testEnvironment": "jsdom",
-    "testMatch": ["**/tests/**/*.test.js"],
+    "testMatch": [
+      "**/tests/**/*.test.js"
+    ],
     "collectCoverageFrom": [
       "*.js",
       "!*.test.js"
diff --git a/popup.js b/popup.js
index a7cf6ad..2dfc249 100644
--- a/popup.js
+++ b/popup.js
@@ -71,10 +71,11 @@ document.addEventListener('DOMContentLoaded', async function () {
 
   async function init() {
     try {
-      loadFilters();
-      renderFilters();
-      setupEventListeners();
-      showFilterView();
+      loadFilters(() => {
+        renderFilters();
+        setupEventListeners();
+        showFilterView();
+      });
     } catch (error) {
       console.error('Failed to initialize:', error);
       // Show error or fallback
@@ -100,7 +101,7 @@ document.addEventListener('DOMContentLoaded', async function () {
     });
   }
 
-  function loadFilters() {
+  function loadFilters(callback) {
     if (typeof FilterState === 'undefined') {
       // Fallback for development/testing
       PopupState.setFilters([
@@ -110,7 +111,7 @@ document.addEventListener('DOMContentLoaded', async function () {
         'Personal',
         'Shopping',
       ]);
-      renderFilters();
+      callback();
       return;
     }
 
@@ -121,7 +122,7 @@ document.addEventListener('DOMContentLoaded', async function () {
       // Load active filter
       FilterState.getActiveFilter(function (activeFilter) {
         PopupState.setActiveFilter(activeFilter);
-        renderFilters();
+        callback();
       });
     });
   }