Install

npm install precss

yarn add precss

PreCSS

PreCSS lets you use Sass-like markup and staged CSS features in CSS.

 $blue: #056ef0;
$column: 200px;

.menu {
  width: calc(4 * $column);
}

.menu_link {
  background: $blue;
  width: $column;
}

/* becomes */

.menu {
  width: calc(4 * 200px);
}

.menu_link {
  background: #056ef0;
  width: 200px;
}

PreCSS combines Sass-like syntactical sugar — like variables, conditionals, and
iterators — with emerging CSS features — like logical and custom properties,
media query ranges, and image sets.

Usage

Add PreCSS to your build tool:

 npm install precss --save-dev

Node

Use PreCSS to process your CSS:

 import precss from 'precss';

precss.process(YOUR_CSS);

PostCSS

Add PostCSS to your build tool:

 npm install postcss --save-dev

Use PreCSS as a plugin:

 import postcss from 'postcss';
import precss from 'precss';

postcss([
  precss(/* options */)
]).process(YOUR_CSS);

Gulp

Add Gulp PostCSS to your build tool:

 npm install gulp-postcss --save-dev

Use PreCSS in your Gulpfile:

 import postcss from 'gulp-postcss';
import precss from 'precss';

gulp.task('css', function () {
  return gulp.src('./src/*.css').pipe(
    postcss([
      precss(/* options */)
    ])
  ).pipe(
    gulp.dest('.')
  );
});

Grunt

Add Grunt PostCSS to your build tool:

 npm install grunt-postcss --save-dev

Use PreCSS in your Gruntfile:

 import precss from 'precss';

grunt.loadNpmTasks('grunt-postcss');

grunt.initConfig({
  postcss: {
    options: {
      use: [
        precss(/* options */)
      ]
    },
    dist: {
      src: '*.css'
    }
  }
});