Px to Rem with PostCSS

postcss.js

var pxtorem = require( 'postcss-pxtorem' ),
	pxtoremOptions = {
		replace: false,
		rootValue: 16,
		unitPrecision: 10,
		propWhiteList: [
			'font', 'font-size', 'letter-spacing']
	};

module.exports = {
	dist: {
		options: {
			map: {
				inline: false,
				annotation: 'assets/css/dist/'
			},
			processors: [
				pxtorem(
					pxtoremOptions
				)
			]
		},
		files: [
			{
				expand: true,
				cwd: 'assets/css/src/',
				src: [ '**/*.css' ],
				dest: 'assets/css/dist/',
				ext: '.css'
			}
		]
	}
};