Cansin Acarer

To make sure the path variable you are using does not refer to the parent themes directory, use:

get_stylesheet_directory_uri();

So to inject the style.css in your child theme folder, use this corrected version of the snippet found on this link:

wp_enqueue_style('main-styles', get_stylesheet_directory_uri() . '/style.css', array(), filemtime(get_stylesheet_directory_uri() . '/style.css'), false);