Show a temporary pause of 5seconds when transitioning to next content

We need to show a temporary screen for 5sec before transitioning to next content.

- Design and DOM example in motley for the temporary screen (Bounty: 500)
- Implement in projectx (Bounty: 800)

Start by reviewing the DOM example and design work in motley, then inspect the content-transition flow in projectx. Done means a temporary screen is shown for 5 seconds before the next content appears, with both the motley example and projectx implementation addressed.

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