Im maintaining a wordpress site which uses GeneratePress theme. To extended a child theme solution was used. It is already a quite developed child theme (saying this to avoid dramatic solutions).
For a while I have had issues with CSS cache every time I update the CSS. style.css child stylesheets deliver the cache version instead of the modified one.
I believe that GeneratePress theme is loading parent style.css + child style.css if it exists.
generatepress/functions.php
// Enqueue our CSS.
wp_enqueue_style( 'generate-style-grid', get_template_directory_uri() . "/css/unsemantic-grid{$suffix}.css", false, GENERATE_VERSION, 'all' );
wp_enqueue_style( 'generate-style', get_template_directory_uri() . '/style.css', array( 'generate-style-grid' ), GENERATE_VERSION, 'all' );
wp_enqueue_style( 'generate-mobile-style', get_template_directory_uri() . "/css/mobile{$suffix}.css", array( 'generate-style' ), GENERATE_VERSION, 'all' );
wp_add_inline_style( 'generate-style', generate_base_css() );
// Add the child theme CSS if child theme is active.
if ( is_child_theme() )
wp_enqueue_style( 'generate-child', get_stylesheet_uri(), true, filemtime( get_stylesheet_directory() . '/style.css' ), 'all' );
function theme_css(){
wp_enqueue_style( 'my-theme-style', get_stylesheet_directory_uri().'/style.css', 'generate-style', '1.1', 'all');
}
add_action( 'wp_enqueue_scripts', 'theme_css' );
If you're using Autoptimize as the theme docs suggest here, then you need to delete the cache and your users will see the changes. This quote is from that documentation:
Installing Autoptimize
Reducing the amount of CSS and JS files being loaded on each page load will make a huge difference to your page speed.
Another perk with Autoptimize is it will bundle the CSS generated by your options in the Customizer into an external file, allowing your browser to cache it.
To delete and reset Autoptimize cache: Login to wp-admin and go to Plugins/Autoptimize/Settings to delete the cache and it will do that and start a new cache for you. There's also an Autoptimize item in the top menu bar in wp-admin; it's handy for this too.