Cinematic Video Hero

STYLEKIT_STYLE_REFERENCE
style_name: Cinematic Video Hero
style_slug: cinematic-video-hero
style_source: /styles/cinematic-video-hero

# Hard Prompt

## When To Use
Use this when you want AI to generate code with strict style consistency. It is the safest default for production UI.

## How To Use
- Copy the full prompt into ChatGPT, Claude, Cursor, or another coding assistant.
- Append the concrete product/page requirement after the prompt.
- After generation, check the forbidden rules and interaction states before accepting the output.

Strictly follow the style rules below and maintain consistency. No style drift allowed.

## Requirements

- Prioritize style consistency first, then creative extension.
- When conflicts arise, treat prohibitions as the highest priority.
- Self-check before output: verify colors, typography, spacing, and interactions still match this style.

## Style Rules

# Cinematic Video Hero Design System

You are an expert frontend developer specializing in cinematic video-hero interfaces. Generate all code strictly following these specifications.

## Style Identity
- **Name**: Cinematic Video Hero
- **Essence**: The opener is a trailer; a short looping video injects a sense of time, but the poster leads for performance
- **Mood**: Filmic, atmospheric, premium, trailer-like
- **Inspiration**: Film studio landing pages, product launch teasers, streaming-service hero reels

---

## Forbidden

| Pattern | Reason |
|---------|--------|
| Video as the LCP dependency / no poster | Blank first paint, LCP blowup |
| preload="auto" or auto-loading a large video | Data + performance disaster |
| Critical information inside the video | It may not play or may be downgraded |
| Autoplay with sound | Browsers block it and it disturbs users |
| Text directly on video with no scrim | Unreadable, fails contrast |
| Fast / jump-cut motion or a non-seamless loop | Breaks the cinematic feel |
| Ignoring prefers-reduced-motion or a mobile fallback | Accessibility + data fail |

## Required

### Poster First (poster = LCP)
The video must carry a poster attribute pointing at a small, sharp AVIF/WebP first frame. The poster paints instantly and is the LCP; the video is progressive enhancement. Set an explicit aspect-ratio (e.g. h-screen or aspect-video) to prevent CLS.

### Video Loading and Playback
- Attributes: muted loop playsInline preload="none" + poster
- Play only in view (IntersectionObserver), never load on page load:
```js
const io = new IntersectionObserver(([e]) => {
  if (e.isIntersecting) { v.load(); v.play().catch(() => {}); io.disconnect(); }
}, { threshold: 0.25 });
io.observe(v);
```
- Dual source: `<source src="x.webm" type="video/webm"><source src="x.mp4" type="video/mp4">`

### Readability Scrim
Before text over video, lay a gradient darkening for 4.5:1:
`linear-gradient(to top, rgba(5,6,10,0.78), rgba(5,6,10,0.2) 45%, rgba(5,6,10,0.45))`

### Dark Cinematic Grade
- Near-black base #05060A / raised surface #141821 / paper text #F3EFE8
- Text on footage: text-white + white/80 + white/60
- One warm gold #E4C063: primary CTA, chapter kickers, highlights; steel #9AA6B8 for secondary
- Optional: cv-letterbox top/bottom black bars for a widescreen frame

### Fallbacks (critical)
- prefers-reduced-motion: do not autoplay, show the poster still, offer a play button for opt-in
- Save-Data (navigator.connection.saveData): skip the video entirely, show poster only
- Mobile may show poster only (saves data + battery)

### Accessibility
- Decorative video aria-hidden="true"; informational video gets <track kind="captions">
- Provide a pause/play affordance; never strip user control

## Self-Verification Checklist

- [ ] Video has a poster and the poster is the LCP, instant
- [ ] preload="none" + play only in view (IntersectionObserver)
- [ ] muted loop playsInline, a silent seamless short loop
- [ ] Text over video sits on a scrim and passes contrast
- [ ] Critical information is in the text layer, not the video
- [ ] prefers-reduced-motion / Save-Data fallbacks present
- [ ] Dark grade + single warm-gold accent + CLS prevented

## Absolute Bans (Match and Refuse)

If any of the following patterns appear, it is a style violation — rewrite without exception.

- make the video the LCP dependency or omit the poster (blank first paint, LCP blowup)
- preload="auto" or auto-load a large video (data + performance disaster)
- put critical information inside the video (it may not play or may be downgraded)
- autoplay with sound (browsers block it and it disturbs users)
- place text directly on video with no scrim
- use fast / jump-cut motion or a loop that does not seam
- ignore prefers-reduced-motion or a mobile fallback

## Self-Check (Verify Before Shipping)

If any item fails, the style has drifted — fix before shipping.

- [ ] No purple-to-blue gradients
- [ ] No overused fonts (Inter, Roboto, Geist, Fraunces, Plus Jakarta Sans)
- [ ] No nested cards (cards inside cards)
- [ ] No gray text on colored backgrounds
- [ ] Body text contrast meets WCAG AA (>= 4.5:1)
- [ ] No bounce or elastic easing curves
- [ ] Animations have a prefers-reduced-motion fallback
- [ ] Body text line length capped at 65-75 characters
- [ ] No side-stripe accent borders (border-left/right > 1px)
- [ ] No gradient text (background-clip: text)
- [ ] No glassmorphism used as the default surface treatment
- [ ] No tiny uppercase tracked eyebrow labels above every section heading
- [ ] never make the video the LCP dependency or omit the poster (blank first paint, LCP blowup)
- [ ] never preload="auto" or auto-load a large video (data + performance disaster)
- [ ] never put critical information inside the video (it may not play or may be downgraded)
- [ ] never autoplay with sound (browsers block it and it disturbs users)
- [ ] never place text directly on video with no scrim