Movie-grade Explainer — a concept → a cinematic vertical explainer with pixel-perfect HTML overlays

A finished reel = vertical 9:16 + voiceover + full-length music bed + crisp HTML text overlay + 45–90s. Pass `aspect_ratio:"9:16"` to `generate_project` (it threads to every scene), animate in waves of ≤4–5 (or use the Ken-Burns stills fallback when fal's video tier is flaky), stitch with `ffmpeg-concat`, mux `chatterbox-tts` narration over a ducked `music` bed with `audio_fill:"loop"` so the score covers every second, then lay a single `hyperframes-render` document over the whole reel. A silent montage — or one whose music cuts out, or with the equation baked into a blurry frame — is a draft, not a deliverable. See the `short-form-video` skill's *definition of done* and the `hyperframes-overlays` skill for the overlay pattern.