text: const boxes = document.querySelectorAll('.box');
  
  window.addEventListener('scroll', checkBoxes);
  
  checkBoxes();
  
  function checkBoxes(){
      const triggerBottom = window.innerHeight / 5 * 4;
  
      boxes.forEach(box => {
          const boxTop = box.getBoundingClientRect().top;
  
          if(boxTop < triggerBottom){
              box.classList.add('show');
          }else{
              box.classList.remove('show');
          }
      })
  }