hide specials
    document.getElementById('show-special-btn').addEventListener('click', function () {
      const specials = document.getElementById('special-configurations');
      specials.classList.toggle('hidden');
      this.textContent = specials.classList.contains('hidden') ? 'Show special configurations' : 'Hide special configurations';
      if (!specials.classList.contains('hidden')) {
        specials.scrollIntoView({ behavior: 'smooth' });
      }
    });
  </script>
</body>

</html>
