add_action('admin_enqueue_scripts', 'codebykp_enqueue_admin_custom_scripts');
function codebykp_enqueue_admin_custom_scripts() {
    wp_enqueue_style('admin-custom-style', get_template_directory_uri() . '/css/admin-style.css');
    wp_enqueue_script('admin-custom-script', get_template_directory_uri() . '/js/admin-script.js', array('jquery'), null, true);
}