diff --git a/src/frontend/apps/e2e/__tests__/calendar.test.ts b/src/frontend/apps/e2e/__tests__/calendar.test.ts
index ade7c28..000032d 100644
--- a/src/frontend/apps/e2e/__tests__/calendar.test.ts
+++ b/src/frontend/apps/e2e/__tests__/calendar.test.ts
@@ -230,4 +230,29 @@ test.describe('Calendar Application', () => {
       await expect(focusedElement).toBeDefined()
     })
   })
+
+  test.describe('Theme Integration', () => {
+    test('calendar uses contextual CSS tokens, not hardcoded colors', async ({ page }) => {
+      await page.goto('/')
+      await page.waitForSelector('.ec', { timeout: 10000 })
+
+      // Verify a contextual token resolves to a non-empty value
+      const surfaceBg = await page.evaluate(() =>
+        getComputedStyle(document.documentElement)
+          .getPropertyValue('--c--contextuals--background--surface--primary')
+          .trim()
+      )
+      expect(surfaceBg).toBeTruthy()
+
+      // Verify the scheduler toolbar uses the token, not hardcoded white
+      const toolbarBg = await page.evaluate(() => {
+        const el = document.querySelector('.scheduler-toolbar')
+        return el ? getComputedStyle(el).backgroundColor : null
+      })
+      // Should NOT be white (#ffffff = rgb(255, 255, 255))
+      if (toolbarBg) {
+        expect(toolbarBg).not.toBe('rgb(255, 255, 255)')
+      }
+    })
+  })
 })