Fatal error: Uncaught Error: Call to undefined function add_filter() in /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/custom-css/custom-css/preprocessors.php:33 Stack trace: #0 /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/custom-css/custom-css.php(1896): include_once() #1 {main} thrown in /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/custom-css/custom-css/preprocessors.php on line 33