More and more presentations start life as HTML. AI assistants generate them, front-end developers hand-code them, and frameworks make them look great in a browser. Sooner or later, though, someone asks for a PowerPoint file. Conversion tools can bridge that gap, but the quality of the result depends heavily on the deck you feed them. After converting a fair number of decks, I keep a short pre-flight checklist. Running through it takes ten minutes and saves a lot of frustration.

1. Set a fixed slide size

Browsers happily reflow content to any window, but slides have fixed dimensions. Before converting, make sure every slide uses a consistent size, ideally 16:9 at something like 1280 by 720 pixels. If your slides stretch to the viewport, the converter has to guess where a slide begins and ends, and the guess is not always the one you would make.

2. One slide per container

Wrap each slide in its own clearly defined element, such as a section with a shared class.…