diff --git a/packages/docusaurus-theme-classic/src/theme/Navbar/MobileSidebar/Layout/index.tsx b/packages/docusaurus-theme-classic/src/theme/Navbar/MobileSidebar/Layout/index.tsx
index 9d623fcd83..7afe2f823c 100644
--- a/packages/docusaurus-theme-classic/src/theme/Navbar/MobileSidebar/Layout/index.tsx
+++ b/packages/docusaurus-theme-classic/src/theme/Navbar/MobileSidebar/Layout/index.tsx
@@ -5,19 +5,37 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import React, {type ReactNode} from 'react';
+import React, {version, type ReactNode} from 'react';
 import clsx from 'clsx';
 import {useNavbarSecondaryMenu} from '@docusaurus/theme-common/internal';
 import {ThemeClassNames} from '@docusaurus/theme-common';
 import type {Props} from '@theme/Navbar/MobileSidebar/Layout';
 
-function NavbarMobileSidebarPanel({children}: {children: ReactNode}) {
+// TODO Docusaurus v4: remove temporary inert workaround
+//  See https://github.com/facebook/react/issues/17157
+//  See https://github.com/radix-ui/themes/pull/509
+function inertProps(inert: boolean) {
+  const isBeforeReact19 = parseInt(version!.split('.')[0]!, 10) < 19;
+  if (isBeforeReact19) {
+    return {inert: inert ? '' : undefined};
+  }
+  return {inert};
+}
+
+function NavbarMobileSidebarPanel({
+  children,
+  inert,
+}: {
+  children: ReactNode;
+  inert: boolean;
+}) {
   return (
     <div
       className={clsx(
         ThemeClassNames.layout.navbar.mobileSidebar.panel,
         'navbar-sidebar__item menu',
-      )}>
+      )}
+      {...inertProps(inert)}>
       {children}
     </div>
   );
@@ -40,8 +58,12 @@ export default function NavbarMobileSidebarLayout({
         className={clsx('navbar-sidebar__items', {
           'navbar-sidebar__items--show-secondary': secondaryMenuShown,
         })}>
-        <NavbarMobileSidebarPanel>{primaryMenu}</NavbarMobileSidebarPanel>
-        <NavbarMobileSidebarPanel>{secondaryMenu}</NavbarMobileSidebarPanel>
+        <NavbarMobileSidebarPanel inert={secondaryMenuShown}>
+          {primaryMenu}
+        </NavbarMobileSidebarPanel>
+        <NavbarMobileSidebarPanel inert={!secondaryMenuShown}>
+          {secondaryMenu}
+        </NavbarMobileSidebarPanel>
       </div>
     </div>
   );