WCAG Contrast [][postcss]

[![NPM Version][npm-img]][npm-url]
[![Linux Build Status][cli-img]][cli-url]
[![Windows Build Status][win-img]][win-url]
[![Gitter Chat][git-img]][git-url]

[WCAG Contrast] checks CSS for [color contrast compliance] with
[Web Content Accessibility Guidelines (WCAG) 2.0].

``css
.header {
background-color: #444;
color: #000; / throws a warning for a low contrast of only 2.2 /
}

.footer {
/ wcag-params: bold 14pt #777 /
color: #000; / throws no warning when text is bold 14pt and contrast is 4.7 /
}
`

Usage

Add [WCAG Contrast] to your build tool:

`bash
npm install postcss-wcag-contrast --save-dev
`

#### Node

Use [WCAG Contrast] to process your CSS:

`js
require('postcss-wcag-contrast').process(YOUR_CSS);
`

#### PostCSS

Add [PostCSS] to your build tool:

`bash
npm install postcss --save-dev
`

Use [WCAG Contrast] as a plugin:

`js
postcss([
require('postcss-wcag-contrast')()
]).process(YOUR_CSS);
`

#### Gulp

Add [Gulp PostCSS] to your build tool:

`bash
npm install gulp-postcss --save-dev
`

Use [WCAG Contrast] in your Gulpfile:

`js
var postcss = require('gulp-postcss');

gulp.task('css', function () {
return gulp.src('./src/*.css').pipe(
postcss([
require('postcss-wcag-contrast')()
])
).pipe(
gulp.dest('.')
);
});
`

#### Grunt

Add [Grunt PostCSS] to your build tool:

`bash
npm install grunt-postcss --save-dev
`

Use [WCAG Contrast] in your Gruntfile:

`js
grunt.loadNpmTasks('grunt-postcss');

grunt.initConfig({
postcss: {
options: {
use: [
require('postcss-wcag-contrast')()
]
},
dist: {
src: '*.css'
}
}
});
`

Options

$3

Type: String
Default: "AA"

The compliance option specifies the WCAG compliance the CSS will be evaluated
against.

$3

Type: CSS Comment

The wcag-params` specifies additional font size, font weight, background, and
foreground information about the rule.

[npm-url]: https://www.npmjs.com/package/postcss-wcag-contrast
[npm-img]: https://img.shields.io/npm/v/postcss-wcag-contrast.svg
[cli-url]: https://travis-ci.org/jonathantneal/postcss-wcag-contrast
[cli-img]: https://img.shields.io/travis/jonathantneal/postcss-wcag-contrast.svg
[win-url]: https://ci.appveyor.com/project/jonathantneal/postcss-wcag-contrast
[win-img]: https://img.shields.io/appveyor/ci/jonathantneal/postcss-wcag-contrast.svg
[git-url]: https://gitter.im/postcss/postcss
[git-img]: https://img.shields.io/badge/chat-gitter-blue.svg

[WCAG Contrast]: https://github.com/jonathantneal/postcss-wcag-contrast
[PostCSS]: https://github.com/postcss/postcss
[Gulp PostCSS]: https://github.com/postcss/gulp-postcss
[Grunt PostCSS]: https://github.com/nDmitry/grunt-postcss

[color contrast compliance]: https://www.w3.org/TR/WCAG20/#visual-audio-contrast-contrast
[Web Content Accessibility Guidelines (WCAG) 2.0]: https://www.w3.org/TR/WCAG20/