<?php
namespace Sabberworm\CSS\Property;
class KeyframeSelector extends Selector
{
/**
* regexp for specificity calculations
*
* @var string
*/
const SELECTOR_VALIDATION_RX = '/
^(
(?:
[a-zA-Z0-9\x{00A0}-\x{FFFF}_^$|*="\'~\[\]()\-\s\.:#+>]* # any sequence of valid unescaped characters
(?:\\\\.)? # a single escaped character
(?:([\'"]).*?(?<!\\\\)\2)? # a quoted text like [id="example"]
)*
)|
(\d+%) # keyframe animation progress percentage (e.g. 50%)
$
/ux';
}