You're hitting a limitation of jsdom — it doesn't support CSS media queries or actual rendering. So even if you stub innerWidth, CSS like @media (min-width: 768px) won’t trigger.

To fix this:

• Use JS conditions instead of relying on CSS
• Or mock window.matchMedia if you are using useMediaQuery:

vi.stubGlobal('matchmedia', query => ({
 matches: query.includes('min-width: 768px'),
 addListener: () => {},
 removeListener: () => {}
}));

Pure CSS based visibility be tested in Vitest/jsdom, it's not supported.