Change Logo color depending on slick slide class

$('.content-block-slideshow').on('beforeChange', function(event, slick, currentSlide, nextSlide) {
   if ($('.slideshow .slide[data-id="' + nextSlide + '"]').hasClass('dark')) {
      $('body').addClass('dark');
   } else {
      $('body').removeClass('dark');
   }
});