public static function config($config = []) {
		if (!$config) {
			return ['classes' => static::$_classes, 'unicode' => static::$_unicode];
		}
		if (isset($config['classes'])) {
			static::$_classes = $config['classes'] + static::$_classes;
		}
		if (isset($config['unicode'])) {
			static::$_unicode = $config['unicode'];
		}
	}