1. You should see no red rectangles or squares before or during the text
  2. You should see a green square below
  3. Click the Go full screen button below
    • The page should enter full screen mode, with the green square turning into a thick green horizontal line.
    • The browser might display a permission window asking you to allow full screen on this page. Allow it.
  4. Exit full screen (e.g. by pressing Esc)
    • The green line should turn back into a green square and all the other initial content should become visible again.
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