Nice! Something similar but maybe not so extreme is Deck Set. https://www.deckset.com/
Write markdown and it does the design for you.
DeckSet is great, but is quite limited in terms of allowing theme customization. If they allowed themes to be modified directly with CSS — or better, YAML/TOML/JSOn, that'd be excellent.
I've been looking very closely at Marp[1], which is a engineer-focused solution to this.