diff --git a/resources/js/react/layouts/AuthCardLayout.tsx b/resources/js/react/layouts/AuthCardLayout.tsx
index bd6d703..9c25cdf 100644
--- a/resources/js/react/layouts/AuthCardLayout.tsx
+++ b/resources/js/react/layouts/AuthCardLayout.tsx
@@ -47,14 +47,14 @@ export default function AuthCardLayout({
                             <CardDescription>{description}</CardDescription>
                         </CardHeader>
                         <CardContent className="px-8">
-                            {(status || error) && (
+                            {status || error ? (
                                 <div data-testid="alert">
                                     <AlertMessage
                                         message={status || error}
                                         variant={status ? 'success' : 'error'}
                                     />
                                 </div>
-                            )}
+                            ) : null}
                             {children}
                         </CardContent>
                     </Card>
diff --git a/tests/e2e/tests/sidebar.spec.ts b/tests/e2e/tests/sidebar.spec.ts
new file mode 100644
index 0000000..b01110b
--- /dev/null
+++ b/tests/e2e/tests/sidebar.spec.ts
@@ -0,0 +1,116 @@
+import { test, expect } from '@e2e/fixtures';
+
+test.describe.parallel('Sidebar layout', () => {
+    test('renders tenant switcher in sidebar header', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+        await expect(page).toHaveURL('/dashboard');
+
+        await expect(page.getByTestId('tenant-switcher')).toBeVisible();
+    });
+
+    test('user dropdown contains language and theme selectors', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await page.getByTestId('user-menu-trigger').click();
+
+        await expect(page.getByTestId('language-selector-trigger')).toBeVisible();
+        await expect(page.getByTestId('theme-selector-trigger')).toBeVisible();
+    });
+
+    test('language selector submenu opens', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('language-selector-trigger').click();
+
+        await expect(page.locator('[data-slot="dropdown-menu-sub-content"]')).toBeVisible();
+    });
+
+    test('theme selector submenu opens', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('theme-selector-trigger').click();
+
+        await expect(page.locator('[data-slot="dropdown-menu-sub-content"]')).toBeVisible();
+    });
+});
+
+test.describe('Theme persistence', () => {
+    test('dark theme persists across navigation via cookie', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+        await expect(page).toHaveURL(/dashboard/);
+
+        // Select dark via the UI — this writes localStorage + cookie
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('theme-selector-trigger').click();
+        await page.getByRole('menuitem', { name: 'Dark' }).click();
+
+        await expect(page.locator('html')).toHaveClass(/dark/);
+
+        // Navigate to another page and back — server should render class="dark" from cookie
+        await page.goto(page.url());
+
+        await expect(page.locator('html')).toHaveClass(/dark/);
+    });
+
+    test('light theme does not add dark class after navigation', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+        await expect(page).toHaveURL(/dashboard/);
+
+        // Select light via the UI
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('theme-selector-trigger').click();
+        await page.getByRole('menuitem', { name: 'Light' }).click();
+
+        await expect(page.locator('html')).not.toHaveClass(/dark/);
+
+        await page.goto(page.url());
+
+        await expect(page.locator('html')).not.toHaveClass(/dark/);
+    });
+
+    test('system preference dark mode applied before hydration', async ({ page, credentials, loginAs }) => {
+        await page.emulateMedia({ colorScheme: 'dark' });
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await expect(page.locator('html')).toHaveClass(/dark/);
+    });
+
+    test('dark mode toggle writes to appearance localStorage key, not vueuse-dark', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('theme-selector-trigger').click();
+        await page.getByTestId('color-mode-dark').click();
+        await page.waitForFunction(() => localStorage.getItem('appearance') === 'dark');
+
+        const stored = await page.evaluate(() => localStorage.getItem('appearance'));
+        expect(stored).toBe('dark');
+
+        const wrongKey = await page.evaluate(() => localStorage.getItem('vueuse-dark'));
+        expect(wrongKey).toBeNull();
+    });
+
+    test('dark mode toggle writes appearance cookie for server-side persistence', async ({ page, credentials, loginAs }) => {
+        await loginAs(credentials.user);
+        await page.goto('/dashboard');
+
+        await page.getByTestId('user-menu-trigger').click();
+        await page.getByTestId('theme-selector-trigger').click();
+        await page.getByTestId('color-mode-dark').click();
+        await page.waitForFunction(() => document.cookie.includes('appearance=dark'));
+
+        const cookies = await page.context().cookies();
+        const appearanceCookie = cookies.find((c) => c.name === 'appearance');
+        expect(appearanceCookie?.value).toBe('dark');
+    });
+});