Issue #3443577 by Gauravvvv, rishabjasrotia, Rajan Kumar@2026, mherchel,...

Issue #3443577 by Gauravvvv, rishabjasrotia, Rajan Kumar@2026, mherchel, finnsky, ckrina: Navigation overlay z-index is not defined

(cherry picked from commit 4ce35031)

core/modules/navigation/layouts/navigation.html.twig

@@ -83,7 +83,7 @@
     </nav>
   </div>
 </aside>
-<div class="admin-toolbar-overlay" aria-controls="admin-toolbar"></div>
+<div class="admin-toolbar-overlay" aria-controls="admin-toolbar" data-drupal-admin-styles></div>
 <script>
   if (localStorage.getItem('Drupal.navigation.sidebarExpanded') !== 'false' && (window.matchMedia('(min-width: 1024px)').matches)) {
     document.documentElement.setAttribute('data-admin-toolbar', 'expanded');