How to leave the working file unchanged when using cssnano?

Question

css

I'm trying to learn gupl in conjunction with Phpstorm. It is necessary that css is minified and uploaded to the server automatically.
When running the gulpfile.js task

gulp.task('nano ', function() {
    return gulp.src('assets/templates/css/styles.css')
        .pipe(cssnano())
        .pipe(gulp.dest('assets/templates/css/'));
});

the styles.css file itself is minified, which I don't need. How to make the minification saved in a separate file, and the worker is not touched?