text: let acc = document.getElementsByClassName('accordion');
  let i;
  
  for (i = 0; i < acc.length; i++) {
      acc[i].addEventListener('click', function () {
          this.classList.toggle('active');
          let panel = this.nextElementSibling;
          if (panel.style.maxHeight) 
              panel.style.maxHeight = null;
          else 
              panel.style.maxHeight = panel.scrollHeight + 'px';
      });
  }