1. You should see no red rectangles or squares before or during the text
  2. Below, you should see a green square, a light blue square and another green square, stacked vertically
  3. Click the Go full screen button below
    • The page should enter full screen mode, with only the light blue square being visible.
    • 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)
    • All initial content should be visible again.
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