PostCSS is a tool for transforming styles with JS plugins. These plugins can lint your CSS, support variables and mixins, transpile future CSS syntax, inline images, and more.
PostCSS is used by industry leaders including Wikipedia, Twitter, Alibaba, and JetBrains. The Autoprefixer PostCSS plugin is one of the most popular CSS processors.
PostCSS takes a CSS file and provides an API to analyze and modify its rules (by transforming them into an Abstract Syntax Tree). This API can then be used by plugins to do a lot of useful things, e.g., to find errors automatically, or to insert vendor prefixes.
Support / Discussion: Gitter
Twitter account: @postcss
VK.com page: postcss
中文翻译: docs/README-cn.md
For PostCSS commercial support (consulting, improving the front-end culture of your company, PostCSS plugins), contact Evil Martians at [email protected].
Sponsorship
PostCSS needs your support. We are accepting donations at Open Collective.
Plugins
Currently, PostCSS has more than 200 plugins. You can find all of the plugins in the plugins list or in the searchable catalog. Below is a list of our favorite plugins — the best demonstrations of what can be built on top of PostCSS.
If you have any new ideas, PostCSS plugin development is really easy.
Solve Global CSS Problem
postcss-use
allows you to explicitly set PostCSS plugins within CSS and execute them only for the current file.postcss-modules
andreact-css-modules
automatically isolate selectors within components.postcss-autoreset
is an alternative to using a global reset that is better for isolatable components.postcss-initial
addsall: initial
support, which resets all inherited styles.cq-prolyfill
adds container query support, allowing styles that respond to the width of the parent.
Use Future CSS, Today
autoprefixer
adds vendor prefixes, using data from Can I Use.postcss-preset-env
allows you to use future CSS features today.
Better CSS Readability
precss
contains plugins for Sass-like features, like variables, nesting, and mixins.postcss-sorting
sorts the content of rules and at-rules.postcss-utilities
includes the most commonly used shortcuts and helpers.short
adds and extends numerous shorthand properties.
Images and Fonts
postcss-assets
inserts image dimensions and inlines files.postcss-sprites
generates image sprites.font-magician
generates all the@font-face
rules needed in CSS.postcss-inline-svg
allows you to inline SVG and customize its styles.postcss-write-svg
allows you to write simple SVG directly in your CSS.
Linters
stylelint
is a modular stylesheet linter.stylefmt
is a tool that automatically formats CSS accordingstylelint
rules.doiuse
lints CSS for browser support, using data from Can I Use.colorguard
helps you maintain a consistent color palette.
Other
postcss-rtl
combines both-directional (left-to-right and right-to-left) styles in one CSS file.cssnano
is a modular CSS minifier.lost
is a feature-richcalc()
grid system.rtlcss
mirrors styles for right-to-left locales.
Syntaxes
PostCSS can transform styles in any syntax, not just CSS. If there is not yet support for your favorite syntax, you can write a parser and/or stringifier to extend PostCSS.
sugarss
is a indent-based syntax like Sass or Stylus.postcss-syntax
switch syntax automatically by file extensions.postcss-html
parsing styles in<style>
tags of HTML-like files.postcss-markdown
parsing styles in code blocks of Markdown files.postcss-jsx
parsing CSS in template / object literals of source files.postcss-styled
parsing CSS in template literals of source files.postcss-scss
allows you to work with SCSS (but does not compile SCSS to CSS).postcss-sass
allows you to work with Sass (but does not compile Sass to CSS).postcss-less
allows you to work with Less (but does not compile LESS to CSS).postcss-less-engine
allows you to work with Less (and DOES compile LESS to CSS using true Less.js evaluation).postcss-js
allows you to write styles in JS or transform React Inline Styles, Radium or JSS.postcss-safe-parser
finds and fixes CSS syntax errors.midas
converts a CSS string to highlighted HTML.
Articles
- Some things you may think about PostCSS… and you might be wrong
- What PostCSS Really Is; What It Really Does
- PostCSS Guides
More articles and videos you can find on awesome-postcss list.
Books
- Mastering PostCSS for Web Design by Alex Libby, Packt. (June 2016)
Usage
You can start using PostCSS in just two steps:
- Find and add PostCSS extensions for your build tool.
- Select plugins and add them to your PostCSS process.
CSS-in-JS
The best way to use PostCSS with CSS-in-JS is astroturf
.
Add its loader to your webpack.config.js
:
module.exports = {
module: {
rules: [
{
test: /\.css$/,
use: ['style-loader', 'postcss-loader'],
},
{
test: /\.jsx?$/,
use: ['babel-loader', 'astroturf/loader'],
}
]
}
}
Then create postcss.config.js
:
module.exports = {
plugins: [
require('autoprefixer'),
require('postcss-nested')
]
}
Parcel
Parcel has built-in PostCSS support. It already uses Autoprefixer
and cssnano. If you want to change plugins, create postcss.config.js
in project’s root:
module.exports = {
plugins: [
require('autoprefixer'),
require('postcss-nested')
]
}
Parcel will even automatically install these plugins for you.
Please, be aware of the several issues in Version 1. Notice, Version 2 may resolve the issues via issue #2157.
Webpack
Use postcss-loader
in webpack.config.js
:
module.exports = {
module: {
rules: [
{
test: /\.css$/,
exclude: /node_modules/,
use: [
{
loader: 'style-loader',
},
{
loader: 'css-loader',
options: {
importLoaders: 1,
}
},
{
loader: 'postcss-loader'
}
]
}
]
}
}
Then create postcss.config.js
:
module.exports = {
plugins: [
require('precss'),
require('autoprefixer')
]
}
Gulp
Use gulp-postcss
and gulp-sourcemaps
.
gulp.task('css', () => {
const postcss = require('gulp-postcss')
const sourcemaps = require('gulp-sourcemaps')
return gulp.src('src/**/*.css')
.pipe( sourcemaps.init() )
.pipe( postcss([ require('precss'), require('autoprefixer') ]) )
.pipe( sourcemaps.write('.') )
.pipe( gulp.dest('build/') )
})
npm Scripts
To use PostCSS from your command-line interface or with npm scripts
there is postcss-cli
.
postcss --use autoprefixer -c options.json -o main.css css/*.css
Browser
If you want to compile CSS string in browser (for instance, in live edit tools like CodePen), just use Browserify or webpack. They will pack PostCSS and plugins files into a single file.
To apply PostCSS plugins to React Inline Styles, JSS, Radium
and other CSS-in-JS, you can use postcss-js
and transforms style objects.
var postcss = require('postcss-js')
var prefixer = postcss.sync([ require('autoprefixer') ])
prefixer({ display: 'flex' }) //=> { display: ['-webkit-box', '-webkit-flex', '-ms-flexbox', 'flex'] }
Runners
- Grunt:
grunt-postcss
- HTML:
posthtml-postcss
- Stylus:
poststylus
- Rollup:
rollup-plugin-postcss
- Brunch:
postcss-brunch
- Broccoli:
broccoli-postcss
- Meteor:
postcss
- ENB:
enb-postcss
- Taskr:
taskr-postcss
- Start:
start-postcss
- Connect/Express:
postcss-middleware
JS API
For other environments, you can use the JS API:
const autoprefixer = require('autoprefixer')
const postcss = require('postcss')
const precss = require('precss')
const fs = require('fs')
fs.readFile('src/app.css', (err, css) => {
postcss([precss, autoprefixer])
.process(css, { from: 'src/app.css', to: 'dest/app.css' })
.then(result => {
fs.writeFile('dest/app.css', result.css, () => true)
if ( result.map ) {
fs.writeFile('dest/app.css.map', result.map, () => true)
}
})
})
Read the PostCSS API documentation for more details about the JS API.
All PostCSS runners should pass PostCSS Runner Guidelines.
Options
Most PostCSS runners accept two parameters:
- An array of plugins.
- An object of options.
Common options:
syntax
: an object providing a syntax parser and a stringifier.parser
: a special syntax parser (for example, SCSS).stringifier
: a special syntax output generator (for example, Midas).map
: source map options.from
: the input file name (most runners set it automatically).to
: the output file name (most runners set it automatically).
Treat Warnings as Errors
In some situations it might be helpful to fail the build on any warning
from PostCSS or one of its plugins. This guarantees that no warnings
go unnoticed, and helps to avoid bugs. While there is no option to enable
treating warnings as errors, it can easily be done
by adding postcss-fail-on-warn
plugin in the end of PostCSS plugins:
module.exports = {
plugins: [
require('autoprefixer'),
require('postcss-fail-on-warn')
]
}
Editors & IDE Integration
VS Code
csstools.postcss
adds support for PostCSS,postcss-preset-env
and CSS Modules.
Atom
language-postcss
adds PostCSS and SugarSS highlight.source-preview-postcss
previews your output CSS in a separate, live pane.
Sublime Text
Syntax-highlighting-for-PostCSS
adds PostCSS highlight.
Vim
postcss.vim
adds PostCSS highlight.
WebStorm
WebStorm 2016.3 has built-in PostCSS support.
Security Contact
To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.
For Enterprise
Available as part of the Tidelift Subscription.
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and thousands of other packages are working
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