Restyle the Slides

## Do you have an eye for design?
Help us improve the look of the slide deck.
If you need help, check out the Appendix in the training manual.

Start by reviewing the slide deck and the Appendix in the training manual for the current visual style and any relevant guidance. Define the intended restyling scope before changing anything; done should mean the deck has a consistent, improved appearance that follows the training material's guidance.

Written by the indexing model from the issue text.