From what I understood you want to override some particular CSS properties from style.css of a WordPress theme.
There might be two different situations here which needs different solutions:
- If you are developing your own theme then you can simply edit your functions.php inside your theme files and add any JS or CSS file that you want like this:
wp_enqueue_style( 'handle name', 'your external source address'); wp_enqueue_script( 'handle name', 'your external source address');
I don’t know if you are familiar with WordPress developing conventions but you have to wrap this function inside a custom one and call that after a WordPress hook like this:
function custom_function() {
wp_enqueue_style( 'handle name', 'your external source address' )
wp_enqueue_script( 'handle name', 'your external source address' )
}
add_action( 'wp_enqueue_scripts', 'custom_function' );
- If you are using a theme from the official WordPress repository, then it is not a good practice to make changes to files of that theme, because most likely you will lose all your custom changes when that theme gets updated. Instead, you have to make a child theme for that theme and do as explained previously for functions.php of the child theme.
Defining a child theme is a different topic on it’s own but it’s not a difficult one! Study this page and you will be able to make your own child theme easily:
Child Themes | Theme Developer Handbook
other useful related resources: