/**
 * Abstract Box — Custom stylesheet (retired in 2.2.0)
 *
 * All styles are now consolidated in abstract-box.css.
 * This file is kept to avoid 404 errors on sites that may have
 * cached the old enqueue handle. It intentionally has no rules.
 *
 * @package AbstractBox
 * @since   2.2.0
 * @deprecated
 */