# Bullframe CSS

> Semantic by default. Any stack. Classless when you want it. System dark built in. Accessible defaults. Native CSS, seven builds, ~8 KB gzipped. Zero runtime dependencies. MIT license.

Site: https://bullframecss.marcopontili.com
Repo: https://github.com/marcop135/bullframe.css
npm: bullframe.css
CDN: https://cdn.jsdelivr.net/npm/bullframe.css

Every docs page is also available as clean Markdown: append `.md` to the path (for example `/getting-started.md`), or send `Accept: text/markdown`. Full corpus: [/llms-full.txt](https://bullframecss.marcopontili.com/llms-full.txt).

## Builds (seven files)

- bullframe.css - class-based, light
- bullframe-dark.css - class-based, always dark
- bullframe-system-default.css - class-based, prefers-color-scheme
- bullframe-classless.css - semantic HTML only, light (no .bf-* classes)
- bullframe-classless-dark.css - classless, always dark
- bullframe-classless-system-default.css - classless, prefers-color-scheme
- bullframe-utilities.css - .bf-* helpers only

## Docs

- [Home](https://bullframecss.marcopontili.com/): Product overview
- [Docs index](https://bullframecss.marcopontili.com/README): Full reference map
- [Getting started](https://bullframecss.marcopontili.com/getting-started): Modes, CDN/npm, starters
- [Migration](https://bullframecss.marcopontili.com/migration): v5 to v6
- [Variables](https://bullframecss.marcopontili.com/variables): `--bf-*` tokens
- [Typography](https://bullframecss.marcopontili.com/typography): Headings, body, lists
- [Layout](https://bullframecss.marcopontili.com/layout): Containers, grid, responsive
- [Forms](https://bullframecss.marcopontili.com/forms): Controls and validation
- [Buttons](https://bullframecss.marcopontili.com/buttons): Button classes
- [Utilities](https://bullframecss.marcopontili.com/utilities): Utility overview
- [Components](https://bullframecss.marcopontili.com/components/): UI patterns
- [Theming](https://bullframecss.marcopontili.com/theming): Themes and customization
- [Dark mode](https://bullframecss.marcopontili.com/theming/dark-mode): System and always-dark
- [Accessibility](https://bullframecss.marcopontili.com/accessibility): a11y defaults
- [Browser support](https://bullframecss.marcopontili.com/browser-support): Target browsers
- [API reference](https://bullframecss.marcopontili.com/api-reference): Generated tokens and classes
- [Agent skills](https://bullframecss.marcopontili.com/agent-skills): Skills for coding agents shipped with the package

## Agent skills

Skills that teach an agent this framework ship in the npm package and are published here:

- [/skills/index.json](https://bullframecss.marcopontili.com/skills/index.json): Skill manifest
- [/api.json](https://bullframecss.marcopontili.com/api.json): Every `.bf-*` class and `--bf-*` token, generated from source

Install into a project with `npx bullframe.css skills install`.

## Install

```html
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bullframe.css">
```

```bash
npm install bullframe.css
```

For a version-pinned CDN URL with Subresource Integrity, see [Getting started](https://bullframecss.marcopontili.com/getting-started) and [/sri.json](https://bullframecss.marcopontili.com/sri.json).

## Note for crawlers

Documentation pages are intended for indexing, live AI context, and training citations (`Content-Signal: search=yes, ai-input=yes, ai-train=yes`).
The interactive kitchen sink at `/kitchen-sink/` is excluded via `robots.txt` and must not be indexed.