Admin Theme customization

Question

You are missing the hyphen in your admin_print_styles hook.

function kd_plugin_admin_menu() {
   /* Register our plugin page */
   $page = add_submenu_page( 'edit.php', 
                             __( 'KD Plugin', 'kdPlugin' ), 
                             __( 'KD Plugin', 'kdPlugin' ),
                             'administrator',
                             __FILE__, 
                             'kd_plugin_manage_menu' );

   /* Using registered $page handle to hook stylesheet loading */
   add_action( 'admin_print_styles-' . $page, 'kd_plugin_admin_styles' );
}