PostCSS Font Weights

PostCSS Font Weights lets you do this in CSS.

h1, h2, h3 {
  font-weight: light;
}

pre {
   font: light 100% monospace;
}

/* becomes */

h1, h2, h3 {
  font-weight: 300;
}

pre {
   font: 300 100% monospace;
}

Common font weights are found in the Font Weight Numeric Values section of the CSS Fonts Specification.

These common font weights are converted to their numeric counterpart.

Usage

Add PostCSS Font Weights to your project:

npm install postcss-font-weights --save-dev

Use PostCSS Font Weights to process your CSS:

const postcssFontWeights = require('postcss-font-weights');

postcssFontWeights.process(YOUR_CSS /*, processOptions, pluginOptions */);

Or use it as a PostCSS plugin:

const postcss = require('postcss');
const postcssFontWeights = require('postcss-font-weights');

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

PostCSS Font Weights runs in all Node environments, with special instructions for:

Options

prefix

The prefix option determines the prefix applied to properties being processed (e.g. x for -x-font-weight). Wrapping dashes (-) are automatically applied.

custom

The custom option determines additional font weight keywords and numeric pairs (e.g. custom: { lite: 300 } for font-weight: lite to become font-weight: 300).