add mobile nav toggle

tests/general.test.ts

@@ -0,0 +1,20 @@
+import { expect, test } from '@playwright/test';
+
+test('page has headline', async ({ page }) => {
+  await page.goto('/');
+  const headline = page.locator('header h1');
+  await expect(headline).toBeVisible();
+  await expect(headline).toHaveText('resumarkdown');
+});
+
+test('nav items work', async ({ page }) => {
+  await page.goto('/');
+  let lastPane = '#pane-preview';
+  for (const pane of ['content', 'style', 'preview']) {
+    const currentPaneId = `pane-${pane}`;
+    await page.locator(`nav li[aria-controls="${currentPaneId}"]`).click();
+    await expect(page.locator(`#${currentPaneId}`)).toBeVisible();
+    await expect(page.locator(lastPane)).toBeHidden();
+    lastPane = `#${currentPaneId}`;
+  }
+});