code: function copyCss() {
    return gulp.src(['./src/assets/stylesheets/*.css'], {base: './src/assets/stylesheets'})
      .pipe(gulp.dest(function (file) {
        return libraryDist + '/dist/css' + file.base.slice(__dirname.length); // save directly to dist
      }));
  }
docs: CSS
   Copy CSS to dist/css