速度匹配的 UI 叙事短片

Velocity-Matched UI Sting Story Film

A high-energy narrative UI sting film that makes a product feel fast, focused, and inevitable through synchronized interface motion and velocity-matched scene transitions.

Style: Kinetic Grid Signal. A sharp, saturated product story where every interface movement accelerates the narrative and resolves into confident proof. Follow references/style-guide.md exactly.

Use this skill when

• Product launches that need a concise, ownable motion identity
• Social campaigns explaining a workflow improvement in under one minute
• Software brands with a measurable outcome and a few visualizable capabilities

Do not use

• Long-form product demos, onboarding tutorials, or feature tours that require persistent interaction detail.
• Lifestyle advertising, cinematic live-action footage, or campaigns that depend on generated imagery.
• Data-heavy executive presentations with more than one proof point per scene.
• To reproduce another company's brand, logo, product UI or copyrighted characters.

Inputs

• Fictional product or campaign name and one-sentence promise
• The workflow friction or customer problem to dramatize
• Two to four product capabilities that can appear as UI rows or panels
• One credible proof metric or outcome
• Preferred social crop safe zone and delivery duration

If something essential is missing, ask one short question before starting. Never invent facts, numbers, quotes or customer names; mark gaps as [needs source].

Workflow

1. Read references/motion-contract.md and references/style-guide.md. Their rules are fixed for this skill.
2. Fill references/scene-map.md from the brief (4-8 scenes, 20-45 s). Never invent product numbers, names or quotes; ask for anything required that is missing.
3. Copy references/composition.html to film/composition.html. Keep the stage, the ambient layer, the progress line and the fit script.
4. Delete the example scenes you do not use, set each scene's text, data-start, data-duration and the absolute animation-delay values, and set <html data-duration> to the sum of scene durations.
5. Apply the style tokens in the :root block exactly as given in the style guide. Do not add colors or webfonts.
6. Open film/composition.html in a browser to preview; it plays in real time. Reload to replay.
7. Render: node scripts/render.mjs film/composition.html --out film.mp4 --fps 30 (install once: npm i -D playwright-core && npx playwright install chromium; FFmpeg must be on PATH).
8. Run the validator below and fix every problem it reports.
9. Extract stills around each cut (ffmpeg -ss <t> -i film.mp4 -frames:v 1 cut.png) and check that nothing is cropped, overlapping or frozen.
10. Run the validator and fix every problem it reports:

``bash node scripts/validate-video.mjs film.mp4 --min-seconds 20 --max-seconds 45 ``

What makes this excellent

• Open with a single high-contrast title frame, then let its exit movement become the first velocity vector of the next scene.
• Represent the problem as a congested interface state with overlapping queues, delayed status changes, or unresolved handoffs.
• Reveal the product through a device scene whose rows enter on the same horizontal trajectory as the preceding words.
• Use the card scene for the clearest product promise, with one metric only and no competing paragraph copy.
• Build proof with bars that accelerate into place in a shared direction, then switch the accent from orange to mint at completion.
• Use the checklist as a visual resolution: each check should arrive on a distinct beat while the grid remains fixed.
• Keep the end card materially simpler than the preceding scenes and hold its brand line long enough for social playback.

Output contract

• film.mp4: H.264, 30 fps, 1280x720, 20-45 seconds.
• film/composition.html: the editable single-file composition that produced it (re-render any time with scripts/render.mjs).
• A hand-off note: the filled scene map, total duration, anything left as a placeholder, and the validator output.
• Render a wide MP4 from a deterministic multi-scene HTML/CSS composition with no external image or font dependencies.
• Maintain readable headline and metric safe zones for later 1:1 or 4:5 social reframing.
• Include a scene timing map so the velocity handoff and end-card hold can be reviewed precisely.

Reference demo and agent run

The preview is a reference render of the bundled composition with sample copy. In a real run the agent rewrites the scenes from the user's brief and assets, re-times the composition and renders a fresh MP4 that meets the output contract above.

Failure rules

• Never hand over a render that fails the validator.
• If the user's screenshots are low resolution, rebuild the surface in HTML instead of upscaling them.
• Music and footage must be supplied and licensed by the user; never download assets.