diff --git a/.Jules/palette.md b/.Jules/palette.md
new file mode 100644
index 0000000..fc75733
--- /dev/null
+++ b/.Jules/palette.md
@@ -0,0 +1,3 @@
+## 2026-06-13 - Add async loading states
+**Learning:** In vanilla JS forms, 'submit' events don't visually block interactions; disabling the submit button with a try/finally block improves perceived performance and prevents duplicate submissions.
+**Action:** Always wrap async form submissions in try/finally to restore button state reliably.
diff --git a/web-demo/css/style.css b/web-demo/css/style.css
index e0d4506..4910dea 100644
--- a/web-demo/css/style.css
+++ b/web-demo/css/style.css
@@ -218,6 +218,16 @@ body {
     transition: all 0.3s ease;
 }
 
+.btn:disabled {
+    opacity: 0.6;
+    cursor: not-allowed;
+}
+
+.btn:focus-visible {
+    outline: 2px solid var(--primary);
+    outline-offset: 2px;
+}
+
 .btn-primary {
     background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
     color: white;
diff --git a/web-demo/js/app.js b/web-demo/js/app.js
index 11508de..375633f 100644
--- a/web-demo/js/app.js
+++ b/web-demo/js/app.js
@@ -65,7 +65,7 @@ class ClimaAI {
 
     setupEventListeners() {
         // Auth
-        document.getElementById('googleSignInBtn').addEventListener('click', () => this.handleGoogleSignIn());
+        document.getElementById('googleSignInBtn').addEventListener('click', (e) => this.handleGoogleSignIn(e));
         document.getElementById('loginForm').addEventListener('submit', (e) => this.handleLogin(e));
         document.getElementById('registerForm').addEventListener('submit', (e) => this.handleRegister(e));
         document.getElementById('showRegister').addEventListener('click', (e) => {
@@ -145,6 +145,16 @@ class ClimaAI {
         const email = document.getElementById('loginEmail').value;
         const password = document.getElementById('loginPassword').value;
 
+        let submitBtn = null;
+        let originalContent = '';
+        if (e && e.submitter) {
+            submitBtn = e.submitter;
+            originalContent = submitBtn.innerHTML;
+            submitBtn.disabled = true;
+            submitBtn.innerHTML = '⏳ Logging in...';
+            submitBtn.setAttribute('aria-busy', 'true');
+        }
+
         try {
             this.showToast('Logging in...', 'info');
             const response = await api.login(email, password);
@@ -155,6 +165,12 @@ class ClimaAI {
             this.checkSubscription();
         } catch (error) {
             this.showToast(error.message || 'Login failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.disabled = false;
+                submitBtn.innerHTML = originalContent;
+                submitBtn.removeAttribute('aria-busy');
+            }
         }
     }
 
@@ -164,6 +180,16 @@ class ClimaAI {
         const email = document.getElementById('registerEmail').value;
         const password = document.getElementById('registerPassword').value;
 
+        let submitBtn = null;
+        let originalContent = '';
+        if (e && e.submitter) {
+            submitBtn = e.submitter;
+            originalContent = submitBtn.innerHTML;
+            submitBtn.disabled = true;
+            submitBtn.innerHTML = '⏳ Creating account...';
+            submitBtn.setAttribute('aria-busy', 'true');
+        }
+
         try {
             this.showToast('Creating account...', 'info');
             const response = await api.register(email, password, name);
@@ -174,6 +200,12 @@ class ClimaAI {
             this.checkSubscription();
         } catch (error) {
             this.showToast(error.message || 'Registration failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.disabled = false;
+                submitBtn.innerHTML = originalContent;
+                submitBtn.removeAttribute('aria-busy');
+            }
         }
     }
 
@@ -185,7 +217,17 @@ class ClimaAI {
         this.showToast('Logged out successfully', 'info');
     }
 
-    async handleGoogleSignIn() {
+    async handleGoogleSignIn(e) {
+        let submitBtn = null;
+        let originalContent = '';
+        if (e && e.currentTarget) {
+            submitBtn = e.currentTarget;
+            originalContent = submitBtn.innerHTML;
+            submitBtn.disabled = true;
+            submitBtn.innerHTML = '⏳ Connecting...';
+            submitBtn.setAttribute('aria-busy', 'true');
+        }
+
         try {
             this.showToast('🔐 Signing in with Google...', 'info');
 
@@ -197,31 +239,37 @@ class ClimaAI {
             // 5. Backend creates/updates user and returns JWT
 
             // For demo purposes, we'll simulate successful OAuth with demo account
-            setTimeout(async () => {
-                try {
-                    // Auto-login with demo account
-                    const response = await api.login('demo@climaai.com', 'Test1234');
-                    this.user = response.user;
-                    this.showToast('✅ Welcome! Signed in with Google', 'success');
-                    this.showScreen('homeScreen');
-                    this.loadWeatherData();
-                    this.checkSubscription();
-                } catch (error) {
-                    this.showToast('Google Sign-In succeeded! Welcome!', 'success');
-                    // Create a demo user object
-                    this.user = {
-                        email: 'google-user@gmail.com',
-                        full_name: 'Google User',
-                        is_premium: true
-                    };
-                    this.isPremium = true;
-                    this.showScreen('homeScreen');
-                    this.loadWeatherData();
-                }
-            }, 1500); // Simulate OAuth redirect delay
+            await new Promise(resolve => setTimeout(resolve, 1500));
+
+            try {
+                // Auto-login with demo account
+                const response = await api.login('demo@climaai.com', 'Test1234');
+                this.user = response.user;
+                this.showToast('✅ Welcome! Signed in with Google', 'success');
+                this.showScreen('homeScreen');
+                this.loadWeatherData();
+                this.checkSubscription();
+            } catch (error) {
+                this.showToast('Google Sign-In succeeded! Welcome!', 'success');
+                // Create a demo user object
+                this.user = {
+                    email: 'google-user@gmail.com',
+                    full_name: 'Google User',
+                    is_premium: true
+                };
+                this.isPremium = true;
+                this.showScreen('homeScreen');
+                this.loadWeatherData();
+            }
 
         } catch (error) {
             this.showToast(error.message || 'Google Sign-In failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.disabled = false;
+                submitBtn.innerHTML = originalContent;
+                submitBtn.removeAttribute('aria-busy');
+            }
         }
     }