SEO & accessibility: OG tags, robots.txt, sitemap, OG image, aria labels, focus trap, keyboard nav

public/app.js

@@ -477,3 +477,39 @@ document.addEventListener('DOMContentLoaded', function() {
     el.addEventListener('click', function(e) { e.preventDefault(); openEmailChange(); });
   });
 });
+
+// === Accessibility: Escape key closes modals, focus trapping ===
+(function() {
+  function getActiveModal() {
+    var modals = ['signupModal', 'recoverModal', 'emailChangeModal'];
+    for (var i = 0; i < modals.length; i++) {
+      var m = document.getElementById(modals[i]);
+      if (m && m.classList.contains('active')) return m;
+    }
+    return null;
+  }
+
+  function closeActiveModal() {
+    var m = getActiveModal();
+    if (!m) return;
+    m.classList.remove('active');
+  }
+
+  document.addEventListener('keydown', function(e) {
+    if (e.key === 'Escape') closeActiveModal();
+
+    // Focus trap inside active modal
+    if (e.key === 'Tab') {
+      var modal = getActiveModal();
+      if (!modal) return;
+      var focusable = modal.querySelectorAll('button:not([disabled]), input:not([disabled]), a[href], [tabindex]:not([tabindex="-1"])');
+      if (focusable.length === 0) return;
+      var first = focusable[0], last = focusable[focusable.length - 1];
+      if (e.shiftKey) {
+        if (document.activeElement === first) { e.preventDefault(); last.focus(); }
+      } else {
+        if (document.activeElement === last) { e.preventDefault(); first.focus(); }
+      }
+    }
+  });
+})();