Deprecated: Sabberworm\CSS\RuleSet\RuleSet::addRule(): Implicitly marking parameter $oSibling as nullable is deprecated, the explicit nullable type must be used instead in C:\Apache24\htdocs\BookStack\vendor\sabberworm\php-css-parser\src\RuleSet\RuleSet.php on line 100

Fatal error: Uncaught Error: Interface "Sabberworm\CSS\Renderable" not found in C:\Apache24\htdocs\BookStack\vendor\sabberworm\php-css-parser\src\RuleSet\RuleSet.php:18 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\BookStack\vendor\sabberworm\php-css-parser\src\RuleSet\RuleSet.php on line 18