Browser keeps caching old style.css from Wordpress theme [closed]

Question

I have a wordpress site. Now I am using a theme and I am substantially overwriting the styles in the stylesheet (style.css) by using inline styles and !important. Problem is that when I refresh the browser, the old styles return. When I press ctrl + f5, my new styles are applied. Ok fine you think... Problem is that even when I completely erase my browsers history, cookies etc, and i load the page with f5, it loads the old styles again. So the only time when it actually loads my new styles are when I press ctrl+f5. I tried different browsers and I do not have any cache plugins on my site...

What can the problem be? Thank you

Answer 1

Try to add it in the functions.php:

add_filter( 'stylesheet_uri', 'wpa_87248_add_style_version' );
function wpa_87248_add_style_version( $url ) {
    $file = get_stylesheet_directory() . '/style.css';
    $version = filemtime( $file );
    return $url . '?v=' . $version;
}