Also, please mind that (as stated in the above mentioned Codex page) using @import for the parent stylesheet is not recommended by WP documentation. The correct method of enqueuing the parent theme stylesheet is to add a wp_enqueue_scripts action and use wp_enqueue_style() in your child theme’s functions.php.
By the way, in case you just want to tweak the CSS of the theme, I would say creating a child theme is not worth the hassle. You can do it with the Simple Custom CSS plugin (https://wordpress.org/plugins/simple-custom-css/). Your custom CSS will stay intact during theme updates. Once you install and activate the plugin, in your Admin Panel please go to ‘Appearance’ > ‘Custom CSS’.