# @csstools/postcss-system-ui-font-family

> Use the `system-ui` keyword

Latest version **2.0.0** (published 2026-01-14) · MIT-0 license · 0 weekly downloads

## Install

```sh
npm install @csstools/postcss-system-ui-font-family
pnpm add @csstools/postcss-system-ui-font-family
yarn add @csstools/postcss-system-ui-font-family
bun add @csstools/postcss-system-ui-font-family
```

## Health

**Score 55/100 (C)** — status: stable.

Positive: esm support; no vulnerabilities; high maintenance score.

Warnings: low downloads; no types.

## Facts

| | |
|---|---|
| Version | 2.0.0 |
| Published | 2026-01-14 |
| First published | 2025-12-04 |
| Weekly downloads | 0 |
| License | MIT-0 |
| TypeScript types | none |
| Module format | ESM |
| Node | >=20.19.0 |
| Dependencies | 2 |
| Unpacked size | 6.7 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 1052 |
| Maintainers | jonathantneal, alaguna, romainmenke |
| Keywords | postcss-plugin |

## Links

- npm: https://www.npmjs.com/package/@csstools/postcss-system-ui-font-family
- Repository: https://github.com/csstools/postcss-plugins
- Homepage: https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-system-ui-font-family#readme
- Issues: https://github.com/csstools/postcss-plugins/issues
- Funding: https://github.com/sponsors/csstools
- npm.io page: https://npm.io/package/@csstools/postcss-system-ui-font-family

## Dependencies (2)

- [@csstools/css-tokenizer](https://npm.io/package/@csstools/css-tokenizer.md) ^4.0.0
- [@csstools/css-parser-algorithms](https://npm.io/package/@csstools/css-parser-algorithms.md) ^4.0.0

## Recent versions

- 2.0.0 (latest) — 2026-01-14
- 1.0.0 — 2025-12-04

## README

# PostCSS System UI Font Family [<img src="https://postcss.github.io/postcss/logo.svg" alt="PostCSS Logo" width="90" height="90" align="right">][PostCSS]

`npm install @csstools/postcss-system-ui-font-family --save-dev`

[PostCSS System UI Font Family] lets you use the `system-ui` keyword following the [CSS Fonts 4 Specification].

```css
.foo {
	font: italic bold 12px/30px system-ui;
	font-family: system-ui;
	--font-family: system-ui;
}

/* becomes */

.foo {
	font: italic bold 12px/30px system-ui;
	font-family: system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,sans-serif;
	--font-family: system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,sans-serif;
}
```

## Usage

Add [PostCSS System UI Font Family] to your project:

```bash
npm install postcss @csstools/postcss-system-ui-font-family --save-dev
```

Use it as a [PostCSS] plugin:

```js
const postcss = require('postcss');
const postcssSystemUIFontFamily = require('@csstools/postcss-system-ui-font-family');

postcss([
	postcssSystemUIFontFamily(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);
```



## Options

### preserve

The `preserve` option determines whether the original notation
is preserved. By default, it is preserved.

```js
postcssSystemUIFontFamily({ preserve: false })
```

```css
.foo {
	font: italic bold 12px/30px system-ui;
	font-family: system-ui;
	--font-family: system-ui;
}

/* becomes */

.foo {
	font: italic bold 12px/30px system-ui;
	font-family: -apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,sans-serif;
	--font-family: -apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,sans-serif;
}
```

[cli-url]: https://github.com/csstools/postcss-plugins/actions/workflows/test.yml?query=workflow/test
[css-url]: https://cssdb.org/#system-ui-font-family
[discord]: https://discord.gg/bUadyRwkJS
[npm-url]: https://www.npmjs.com/package/@csstools/postcss-system-ui-font-family

[PostCSS]: https://github.com/postcss/postcss
[PostCSS System UI Font Family]: https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-system-ui-font-family
[CSS Fonts 4 Specification]: https://drafts.csswg.org/css-fonts-4/#system-ui-def

---
_Source: https://npm.io/package/@csstools/postcss-system-ui-font-family · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._