if authmodal is up, cursor is already in it

frontend/src/components/AuthModal.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from "react";
+import React, { useState, useEffect, useRef, useCallback } from "react";
 import { useAuth } from "../contexts/AuthContext";
 import PasswordStrengthMeter from "./PasswordStrengthMeter";
 import PasswordInput from "./PasswordInput";
@@ -27,6 +27,7 @@ const AuthModal: React.FC<AuthModalProps> = ({
   const [showVerificationModal, setShowVerificationModal] = useState(false);
 
   const { login, register } = useAuth();
+  const modalRef = useRef<HTMLDivElement>(null);
 
   // Update mode when modal is opened with different initialMode
   useEffect(() => {
@@ -35,6 +36,54 @@ const AuthModal: React.FC<AuthModalProps> = ({
     }
   }, [show, initialMode]);
 
+  // Focus trapping for accessibility
+  const handleKeyDown = useCallback((e: KeyboardEvent) => {
+    if (e.key !== "Tab" || !modalRef.current) return;
+
+    const focusableElements = modalRef.current.querySelectorAll<HTMLElement>(
+      'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
+    );
+    const focusableArray = Array.from(focusableElements).filter(
+      (el) => !el.hasAttribute("disabled") && el.offsetParent !== null
+    );
+
+    if (focusableArray.length === 0) return;
+
+    const firstElement = focusableArray[0];
+    const lastElement = focusableArray[focusableArray.length - 1];
+
+    if (e.shiftKey) {
+      // Shift + Tab: if on first element, go to last
+      if (document.activeElement === firstElement) {
+        e.preventDefault();
+        lastElement.focus();
+      }
+    } else {
+      // Tab: if on last element, go to first
+      if (document.activeElement === lastElement) {
+        e.preventDefault();
+        firstElement.focus();
+      }
+    }
+  }, []);
+
+  // Set up focus trap and initial focus when modal is shown
+  useEffect(() => {
+    if (show && !showForgotPassword && !showVerificationModal) {
+      document.addEventListener("keydown", handleKeyDown);
+
+      // Focus the first input element when modal opens
+      if (modalRef.current) {
+        const firstInput = modalRef.current.querySelector<HTMLElement>('input');
+        firstInput?.focus();
+      }
+
+      return () => {
+        document.removeEventListener("keydown", handleKeyDown);
+      };
+    }
+  }, [show, showForgotPassword, showVerificationModal, handleKeyDown]);
+
   const resetModal = () => {
     setError("");
     setEmail("");
@@ -119,7 +168,7 @@ const AuthModal: React.FC<AuthModalProps> = ({
           style={{ backgroundColor: "rgba(0,0,0,0.5)" }}
         >
           <div className="modal-dialog modal-dialog-centered">
-            <div className="modal-content">
+            <div className="modal-content" ref={modalRef}>
             <div className="modal-header border-0 pb-0">
               <button
                 type="button"