Gulpfile.js

gulp.task('sass', function() {
    return gulp.src(config.sass)
               .pipe($.plumber())
               .pipe($.sass())
               .pipe($.autoprefixer())
               .pipe($.if(isDev, gulp.dest(config.tmp)))
               .pipe($.if(isBuild, $.minifyCss()))
               .pipe($.if(isBuild, gulp.dest(config.dist)))
               .pipe($.if(isDev, reload({stream: true})));
});

gulp.task('css', function() {
    return gulp.src(config.css)
               .pipe($.plumber())
               .pipe($.autoprefixer())
               .pipe($.if(isDev, gulp.dest(config.tmp)))
               .pipe($.if(isBuild, $.minifyCss()))
               .pipe($.if(isBuild, gulp.dest(config.dist)))
               .pipe($.if(isDev, reload({stream: true})));
});