gulpfile.js

const fs = require('fs');
const path = require('path');

const gulp = require('gulp');
const rimraf = require('rimraf');
const rename = require('gulp-rename');

const postcss = require('gulp-postcss');
const postcssImport = require('postcss-import');
const postcssCsso = require('postcss-csso');
const postcssMinMax = require('postcss-media-minmax');

/**
 * Processing CSS
 */

const getPostcssTask = () =>
	postcss([postcssImport, postcssCsso, postcssMinMax]);

gulp.task('styles::base::postcss', () => {
	return gulp
		.src('src/styles/styles.css')
		.pipe(getPostcssTask())
		.pipe(rename('styles/styles.min.css'))
		.pipe(gulp.dest('dist/'));
});

gulp.task('styles::schemes::postcss', () => {
	return gulp
		.src('src/styles/schemes/*.css')
		.pipe(getPostcssTask())
		.pipe(gulp.dest('dist/styles/schemes'));
});

gulp.task('fonts::copy', () => {
	return gulp.src('src/fonts/**').pipe(gulp.dest('dist/fonts'));
});

gulp.task(
	'build',
	gulp.series(
		'styles::base::postcss',
		'styles::schemes::postcss',
		'fonts::copy'
	)
);