// var criticalCss = require('gulp-critical-css'),

//example task gulp css

gulp.task('css:build', function () {
    return gulp.src(path.src.css)
        .pipe(rigger())
        .on('error', handleError)
        .pipe(sass())
        .on('error', handleError)
        .pipe(prefixer({
            browsers: ['last 15 versions'],
            cascade: false,
            grid: true
        }))
        .pipe(csscomb())
        .pipe(reload({ stream: true }))
        //...



        //here begin handle critical
        .pipe(criticalCss())
        .pipe(rename({suffix: '.min'}))
        .pipe(cssmin())
        .pipe(gulp.dest(path.dist.css))
});