text: Title: Restyle the documentation landing page
  Body: This is a good issue for anyone with markdown experience who enjoys the styling/design aspect rather than writing copy. There's no knowledge of Vizro required.
  
  The current landing page for documentation is rather bland https://vizro.readthedocs.io/en/stable/ and the presentation could potentially be improved.
  
  It would be great to have some styling to improve it. We can start with the copy we have (although we do need to add a section to link to the demo example in the repo). Some basic redesign is all that is needed to boost the look and feel. 