Build the deck the way a designer does. Decide the narrative and the type/color/spacing system first, then write the slides as content and let a script render them so every slide inherits the same scale. A deck that looks designed got that way systematically: the working parts are one type ramp, one restrained palette at AA contrast, a spacing grid, and one idea per slide, with the default-template look as the failure to avoid.

Push the work down the determinism ladder. The model owns only the words and the archetype choice per slide. Geometry, color, and font sit in a reference template (exact and repeatable), and scripts/render.sh runs the render so the same Markdown yields the same deck. Hand-writing python-pptx geometry every run is the anti-pattern this skill removes.

references/beautiful-decks.md carries the design system, the slide archetypes with layout specs, chart and image treatment, and the failure modes. Read that reference for design judgment and leave the render to render.sh.

Steps

Outline the deck. Name the audience, the single takeaway, and the slide-by-slide arc, one idea per slide, before opening an editor. The arc is complete once each planned slide maps to one archetype from the reference (title, section, content, data, quote, or closing) and no slide carries two ideas.
Write the slides as Markdown. Emit one file where a level-1 heading (#) starts each slide and bullets or a short statement carry that slide's single idea, drawing the narrative and the wording from step 1. This step is the model's content work. The draft is done once every slide opens with one # heading, every body holds one claim as phrases rather than full paragraphs, and no slide runs past five bullets.
Apply brand and design via a reference template. Produce a baseline template with pandoc -o reference.pptx --print-default-data-file reference.pptx, then restyle that baseline once in PowerPoint (theme colors, theme fonts, slide masters) to the tokens named in ../../design/brandkit/SKILL.md and ../../design/frontend-design/SKILL.md, keeping the design principles in references/beautiful-decks.md. The template is ready once the master carries one type ramp, every text pair clears AA contrast (4.5:1, or 3:1 for large text), and the family count is at most two.
Render the deck. Run bash scripts/render.sh <content.md> <out.pptx> [reference.pptx], passing the step-3 template as the third argument so the brand applies. The render succeeds once the script prints wrote <out.pptx> and exits zero.
Verify by reopening. Run unzip -l <out.pptx> and read the archive listing. The deck is valid once the listing shows ppt/presentation.xml.
Polish to the design checklist. Run the deck against the reference checklist (type scale, two fonts or fewer, palette and AA contrast, spacing on the grid, one idea per slide, visual hierarchy, no clip-art, no wall-of-text) and revise each failing line in the Markdown or the template. Polish is complete once every checklist line holds or carries a written, justified exception.