autoprefixer

# Autoprefixer

<img align="right" width="94" height="71"
     src="https://postcss.github.io/autoprefixer/logo.svg"
     title="Autoprefixer logo by Anton Lovchikov">

[PostCSS] plugin to parse CSS and add vendor prefixes to CSS rules using values
from [Can I Use]. It is recommended by Google and used in Twitter and Alibaba.

Write your CSS rules without vendor prefixes (in fact, forget about them
entirely):

```css
::placeholder {
  color: gray;
}

.image {
  width: stretch;
}
```

Autoprefixer will use the data based on current browser popularity and property
support to apply prefixes for you. You can try the [interactive demo]
of Autoprefixer.

```css
::-moz-placeholder {
  color: gray;
}
::placeholder {
  color: gray;
}

.image {
  width: -moz-available;
  width: -webkit-fill-available;
  width: stretch;
}
```

Twitter account for news and releases: [@autoprefixer].

---

<img src="https://cdn.evilmartians.com/badges/logo-no-label.svg" alt="" width="22" height="16" />  Autoprefixer is built by <b><a href="https://evilmartians.com/">Evil Martians</a></b>, an American design and engineering consultancy for <b>developer tools, AI, and cybersecurity startups</b>.

---

[interactive demo]: https://autoprefixer.github.io/
[@autoprefixer]: https://twitter.com/autoprefixer
[Can I Use]: https://caniuse.com/
[PostCSS]: https://github.com/postcss/postcss

## Contents

- [Contents](#contents)
- [Browsers](#browsers)
- [FAQ](#faq)
  - [Does Autoprefixer polyfill Grid Layout for IE?](#does-autoprefixer-polyfill-grid-layout-for-ie)
  - [Does it add polyfills?](#does-it-add-polyfills)
  - [Why doesn’t Autoprefixer add prefixes to `border-radius`?](#why-doesnt-autoprefixer-add-prefixes-to-border-radius)
  - [Why does Autoprefixer use unprefixed properties in `@-webkit-keyframes`?](#why-does-autoprefixer-use-unprefixed-properties-in--webkit-keyframes)
  - [How to work with legacy `-webkit-` only code?](#how-to-work-with-legacy--webkit--only-code)
  - [Does Autoprefixer add `-epub-` prefix?](#does-autoprefixer-add--epub--prefix)
  - [Why doesn’t Autoprefixer transform generic font-family `system-ui`?](#why-doesnt-autoprefixer-transform-generic-font-family-system-ui)
- [Usage](#usage)
  - [Gulp](#gulp)
  - [Webpack](#webpack)
  - [CSS-in-JS](#css-in-js)
  - [CLI](#cli)
  - [Other Build Tools](#other-build-tools)
    - [Preprocessors](#preprocessors)
    - [GUI Tools](#gui-tools)
  - [JavaScript](#javascript)
  - [Text Editors and IDE](#text-editors-and-ide)
- [Warnings](#warnings)
- [Disabling](#disabling)
  - [Prefixes](#prefixes)
  - [Features](#features)
  - [Control Comments](#control-comments)
- [Options](#options)
- [Environment Variables](#environment-variables)
  - [Using environment variables to support CSS Grid prefixes in Create React App](#using-environment-variables-to-support-css-grid-prefixes-in-create-react-app)
- [Grid Autoplacement support in IE](#grid-autoplacement-support-in-ie)
  - [Beware of enabling autoplacement in old projects](#beware-