diff --git a/.Jules/palette.md b/.Jules/palette.md
new file mode 100644
index 0000000..8b0fd1f
--- /dev/null
+++ b/.Jules/palette.md
@@ -0,0 +1,4 @@
+
+## 2024-05-18 - Safe Async Form Submissions
+**Learning:** When adding loading states to vanilla JS form buttons, `e.submitter` must be null-checked to avoid TypeErrors. Additionally, state restoration (restoring text, disabling `aria-busy`, and re-enabling the button) must be placed in a `finally` block to ensure the UI remains usable regardless of network success or failure.
+**Action:** Always wrap `e.submitter` state changes in a conditional and use `finally` for UI recovery in async DOM operations.
diff --git a/web-demo/css/style.css b/web-demo/css/style.css
index e0d4506..f1365ad 100644
--- a/web-demo/css/style.css
+++ b/web-demo/css/style.css
@@ -229,6 +229,18 @@ body {
     box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
 }
 
+.btn:disabled {
+    opacity: 0.6;
+    cursor: not-allowed;
+    transform: none !important;
+    box-shadow: none !important;
+}
+
+.btn:focus-visible {
+    outline: 2px solid var(--primary);
+    outline-offset: 2px;
+}
+
 .btn-google {
     background: white;
     color: #3c4043;
diff --git a/web-demo/js/app.js b/web-demo/js/app.js
index 11508de..515531e 100644
--- a/web-demo/js/app.js
+++ b/web-demo/js/app.js
@@ -145,6 +145,15 @@ class ClimaAI {
         const email = document.getElementById('loginEmail').value;
         const password = document.getElementById('loginPassword').value;
 
+        const submitBtn = e.submitter;
+        let originalText = '';
+        if (submitBtn) {
+            originalText = submitBtn.innerHTML;
+            submitBtn.innerHTML = '⏳ Logging in...';
+            submitBtn.disabled = true;
+            submitBtn.setAttribute('aria-busy', 'true');
+        }
+
         try {
             this.showToast('Logging in...', 'info');
             const response = await api.login(email, password);
@@ -155,6 +164,12 @@ class ClimaAI {
             this.checkSubscription();
         } catch (error) {
             this.showToast(error.message || 'Login failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.innerHTML = originalText;
+                submitBtn.disabled = false;
+                submitBtn.removeAttribute('aria-busy');
+            }
         }
     }