postcss.js

gulp.task('styles', () => {
  // May be useful
  // ----------------
  // webpcss
  // postcss-mixins
  // postcss-simple-extend

  return gulp.src('src/styles.css')
    .pipe($.if(dev, $.sourcemaps.init()))
    .pipe($.postcss([
      require('postcss-import')({
        glob: true,
      }),
      require('postcss-size'),
      require('postcss-for'),
      require('postcss-assets')({
        // loadPaths: ['']
        basePath: 'dist/',
        relativeTo: 'src/',
      }),
      require('postcss-media-minmax')(),
      require('postcss-nested'),
      require('postcss-simple-vars'),
      require('postcss-color-alpha'),
      require('postcss-messages'),
      require('autoprefixer-core'),
      require('postcss-reporter')(),
    ]))
    .pipe($.if(dev, $.sourcemaps.write()))
    .pipe(gulp.dest('dist/'))
});