I think you got it backwards... right now non-tech-savvy people focus on the content with their tooling (PowerPoint, Keynote, Google Slides). Your tooling introduces a new layer of complexity: now they have to learn HTML and css to do the _exact same thing_. What you built looks great, but you have to reconsider who you're marketing it towards. I can't imagine anybody but a programmer using this.

If your goal is to build a platform for presentations like medium is for articles, isn't that what speakerdeck.com already is? If you want to build a better speakerdeck, just say that then? "A better way to create and share slides online"