diff --git a/admin/disable-wp-admin.php b/admin/disable-wp-admin.php
index 6dfd005..d640f4f 100644
--- a/admin/disable-wp-admin.php
+++ b/admin/disable-wp-admin.php
@@ -1,4 +1,69 @@
 <?php
+function helix_is_ready(): bool {
+    // Ensure the built frontend exists before hijacking admin navigation
+    $plugin_base_path = plugin_dir_path(__DIR__); // points to helix/
+    $build_js_path = $plugin_base_path . 'build/index.js';
+    return file_exists($build_js_path) && is_readable($build_js_path);
+}
+
+function helix_normalize_route(string $urlOrPath): string {
+    // Convert absolute URLs to a relative admin route
+    if (preg_match('#^https?://#i', $urlOrPath)) {
+        $parts = wp_parse_url($urlOrPath);
+        $path = isset($parts['path']) ? $parts['path'] : '/wp-admin/';
+        $query = isset($parts['query']) && $parts['query'] !== '' ? '?' . $parts['query'] : '';
+        return $path . $query;
+    }
+
+    // Ensure it starts with /wp-admin (allow optional leading slash)
+    if (preg_match('#^/?wp-admin#', $urlOrPath)) {
+        return str_starts_with($urlOrPath, '/') ? $urlOrPath : '/' . $urlOrPath;
+    }
+
+    return '/wp-admin/';
+}
+
+function helix_should_hijack_admin(): bool {
+    // If user opted into default WP admin, do not hijack
+    if (get_option('helix_use_default_admin', false)) {
+        return false;
+    }
+    // If Helix build is unavailable, do not hijack
+    if (!helix_is_ready()) {
+        return false;
+    }
+    return true;
+}
+
+add_filter('login_redirect', function ($redirect_to, $requested_redirect_to, $user) {
+    // Only modify redirect for successful logins
+    if (is_wp_error($user)) {
+        return $redirect_to;
+    }
+
+    // Respect plugin setting to use default WordPress admin or if Helix is not ready
+    if (!helix_should_hijack_admin()) {
+        return $redirect_to;
+    }
+
+    // Determine the intended post-login target
+    $intended_target = (is_string($requested_redirect_to) && $requested_redirect_to !== '')
+        ? $requested_redirect_to
+        : $redirect_to;
+
+    // If the target is not an admin page, do not override
+    if ($intended_target && !str_contains($intended_target, 'wp-admin')) {
+        return $redirect_to;
+    }
+
+    // Default to the dashboard when no target provided
+    $helix_route = helix_normalize_route($intended_target ?: '/wp-admin/');
+
+    // Send directly to Helix, preserving the original admin route for the React app
+    // Always use '&' because admin.php already has a query string (page=helix)
+    return admin_url('admin.php?page=helix&helix_route=' . urlencode($helix_route));
+}, 10, 3);
+
 add_action('current_screen', function ($current_screen) {
     // Don't redirect if not in admin
     if (!is_admin()) return;
@@ -23,6 +88,11 @@ add_action('current_screen', function ($current_screen) {
         return;
     }
     
+    // Don't redirect if Helix is not ready or the user opted into default admin
+    if (!helix_should_hijack_admin()) {
+        return;
+    }
+
     // Don't redirect critical WordPress admin functions
     global $pagenow;
     $critical_pages = [
@@ -37,11 +107,11 @@ add_action('current_screen', function ($current_screen) {
     if (in_array($pagenow, $critical_pages)) return;
     
     // Capture the current admin URL to pass to Helix for routing
-    $current_url = $_SERVER['REQUEST_URI'];
-    $query_separator = strpos($current_url, '?') !== false ? '&' : '?';
+    $current_url = helix_normalize_route($_SERVER['REQUEST_URI']);
     
     // Build the redirect URL with the original path for React routing
-    $redirect_url = admin_url('admin.php?page=helix' . $query_separator . 'helix_route=' . urlencode($current_url));
+    // Always use '&' because admin.php already has a query string (page=helix)
+    $redirect_url = admin_url('admin.php?page=helix&helix_route=' . urlencode($current_url));
     
     // Redirect all other admin pages to Helix
     wp_redirect($redirect_url);