diff --git a/packages/vitest/src/integrations/env/jsdom-keys.ts b/packages/vitest/src/integrations/env/jsdom-keys.ts
index 677ab3ab8f20..9e731dca0bbc 100644
--- a/packages/vitest/src/integrations/env/jsdom-keys.ts
+++ b/packages/vitest/src/integrations/env/jsdom-keys.ts
@@ -181,6 +181,8 @@ const LIVING_KEYS = [
   'Image',
   'Audio',
   'Option',
+
+  'CSS',
 ]
 
 const OTHER_KEYS = [
diff --git a/test/core/test/environments/happy-dom.spec.ts b/test/core/test/environments/happy-dom.spec.ts
index ecb80ade1c9e..6ebf212397e2 100644
--- a/test/core/test/environments/happy-dom.spec.ts
+++ b/test/core/test/environments/happy-dom.spec.ts
@@ -1,6 +1,6 @@
 // @vitest-environment happy-dom
 
-import { afterEach, test, vi } from 'vitest'
+import { afterEach, expect, test, vi } from 'vitest'
 
 afterEach(() => {
   vi.useRealTimers()
@@ -9,3 +9,9 @@ afterEach(() => {
 test('fake timers don\'t fail when using empty config', () => {
   vi.useFakeTimers({})
 })
+
+test('global CSS is injected correctly', () => {
+  expect(CSS).toBeDefined()
+  expect(CSS.escape).toBeDefined()
+  expect(CSS.supports).toBeDefined()
+})