# Tailwind

> Tailwind CSS v4.2 browser-runtime patterns for FrameVideo compositions. Use when scaffolding or editing projects created with `framevideo init --tailwind`, writing Tailwind utility classes in composition HTML, adding CSS-first Tailwind v4 theme tokens, debugging v3 vs v4 syntax, or deciding when to compile Tailwind to CSS instead of using the browser runtime.

- Skill: `chanjing-ai/tailwind` (Agent Skill)
- Install (CLI): `npx skillmds@latest add chanjing-ai/tailwind`
- Raw SKILL.md: https://api.skillmd.com/api/skills/chanjing-ai/tailwind/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: chanjing-ai (https://skillmd.com/u/chanjing-ai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/chanjing-ai/tailwind

---


# Tailwind CSS for FrameVideo

FrameVideo `init --tailwind` uses the Tailwind browser runtime pinned to `@tailwindcss/browser@4.2.4`. Treat that as Tailwind v4, not v3.

This skill is for composition HTML generated by the CLI. It is not for `packages/studio`, which still uses Tailwind v3 internally with `tailwind.config.js`, PostCSS, and `@tailwind` directives.

## When To Use

Use this skill when:

- **Project uses Tailwind** — created with `framevideo init --tailwind`
- **Writing utility classes** — styling composition HTML with Tailwind classes
- **Custom theme tokens** — defining colors, fonts, spacing with `@theme`
- **v3 to v4 migration** — converting old syntax to CSS-first v4
- **Runtime debugging** — styles missing or `window.__tailwindReady` issues

## Do NOT Use

Avoid this skill for:

- **Non-Tailwind projects** — if project doesn't use Tailwind, write vanilla CSS
- **Studio UI development** — Studio uses v3 with PostCSS (different setup)
- **Backend/CLI code** — this is only for composition HTML
- **When CSS compilation is preferred** — compile Tailwind to CSS for production stability

---

## Quick Start

Create Tailwind-enabled project:

```bash
npx framevideo init my-video --tailwind
cd my-video
```

Use utilities in composition HTML:

```html
<div class="clip" data-start="0" data-duration="5">
  <div class="flex items-center justify-center h-screen">
    <h1 class="text-6xl font-bold text-white">Hello Tailwind</h1>
  </div>
</div>
```

Add custom theme:

```html
<style type="text/tailwindcss">
  @theme {
    --color-brand: oklch(0.68 0.2 252);
    --font-display: "Inter", sans-serif;
  }
</style>

<!-- Use in HTML -->
<h1 class="text-brand font-display">Brand Title</h1>
```

---

## Version Contract

- Pinned runtime: `@tailwindcss/browser@4.2.4`.
- Browser runtime script is injected by the CLI. Do not replace it with `cdn.tailwindcss.com`.
- FrameVideo waits for `window.__tailwindReady` before frame capture starts.
- The readiness shim must stay deterministic: no render-loop polling APIs, no clock-based retries, no runtime network fetches beyond the pinned Tailwind runtime script.
- For offline, locked-down, or production-stable renders, compile Tailwind to CSS and include the stylesheet directly instead of relying on the browser runtime.

## v4 Rules

Tailwind v4 is CSS-first:

```html
<style type="text/tailwindcss">
  @theme {
    --color-brand: oklch(0.68 0.2 252);
    --font-display: "Inter", sans-serif;
  }

  @utility headline-balance {
    text-wrap: balance;
    letter-spacing: 0;
  }
</style>
```

Avoid v3 setup patterns in browser-runtime compositions:

```css
/* Do not use these in Tailwind v4 browser-runtime compositions. */
@tailwind base;
@tailwind components;
@tailwind utilities;
```

Do not add a `tailwind.config.js` just to define colors, fonts, spacing, or utilities for a v4 browser-runtime composition. Use `@theme` and `@utility` in a `text/tailwindcss` style block.

If you truly need an existing JavaScript config for a compiled v4 build, load it explicitly from CSS with `@config`, then validate in the browser. Do not assume v4 auto-detects v3 config files.

## FrameVideo Composition Pattern

Keep Tailwind responsible for static layout and visual style. Keep motion timing in GSAP or another seekable adapter.

```html
<section
  class="clip absolute inset-0 grid place-items-center bg-zinc-950 text-white"
  data-start="0"
  data-duration="5"
  data-track-index="1"
>
  <div class="w-[1280px] max-w-[82vw] text-center">
    <p class="mb-6 text-xl font-medium uppercase tracking-[0.18em] text-cyan-300">
      Render-ready Tailwind
    </p>
    <h1 class="text-7xl font-black leading-none text-balance">
      Utility classes, deterministic frames.
    </h1>
  </div>
</section>
```

For repeated items, prefer class lists plus CSS custom properties over generating class names dynamically:

```html
<span class="inline-block translate-y-[calc(var(--i)*6px)] opacity-80" style="--i: 0"></span>
<span class="inline-block translate-y-[calc(var(--i)*6px)] opacity-80" style="--i: 1"></span>
<span class="inline-block translate-y-[calc(var(--i)*6px)] opacity-80" style="--i: 2"></span>
```

## Dynamic Class Safety

Tailwind's browser runtime scans the current document and generates CSS for class names it can see. Do not build render-critical class names only at seek time:

```js
// Risky: Tailwind may not see every generated class before capture.
element.className = `bg-${color}-500`;
```

Use complete class names in HTML, data attributes, or explicit CSS instead:

```html
<div data-tone="blue" class="bg-blue-500 data-[tone=rose]:bg-rose-500"></div>
```

If a generated class is unavoidable, make sure the full class token appears in a `text/tailwindcss` block before validation.

## Video-Specific Guardrails

- Use stable dimensions: `w-[...]`, `h-[...]`, `aspect-video`, `grid`, `flex`, and fixed padding for video layouts.
- Prefer transforms and opacity for animated properties.
- Keep Tailwind transitions out of render-critical timing unless a seekable runtime owns the state.
- Avoid hover, focus, scroll, viewport, or pointer variants for content that must render deterministically.
- Use explicit border colors. Tailwind v4 changed the default border behavior from v3, so `border border-white/20` is safer than bare `border`.
- Use v4 utility names: `shadow-xs`, `rounded-xs`, `outline-hidden`, `shrink-*`, and `grow-*` where those replacements apply.
- Be careful with modern CSS utilities if the output needs older browser support. Tailwind v4 targets modern browsers.

## Validation

After editing a Tailwind-enabled composition:

```bash
npx framevideo lint
npx framevideo validate
npx framevideo inspect
```

For a render proof:

```bash
npx framevideo render . --workers 1 --quality draft --output tailwind-proof.mp4
```

The validation path should show no missing-style flashes on frame 0. If styles appear in preview but not render, check that `window.__tailwindReady` exists and resolves before capture.

## Quick Debug Checklist

1. Confirm the project was scaffolded with `framevideo init --tailwind`.
2. Confirm the script points to `@tailwindcss/browser@4.2.4`.
3. Confirm `window.__tailwindReady` is present.
4. Replace v3 `@tailwind` directives with v4 browser-runtime CSS.
5. Move custom tokens from `tailwind.config.js` to `@theme`.
6. Replace dynamically assembled classes with complete static tokens.
7. Run `npx framevideo validate` and render a short proof.

## Credits And References

- Tailwind CSS official v4 installation, upgrade, and compatibility docs: https://tailwindcss.com/docs
- Tailwind CSS v4 release notes: https://tailwindcss.com/blog/tailwindcss-v4
- Community Tailwind skills were reviewed for v4 gotchas and skill shape, but this skill keeps the durable contract in-repo and FrameVideo-specific.