setTimeout(() => {
  const demoBtns = document.querySelectorAll('.js-container-target');
  
  // Listen for demo button clicks
  Array.prototype.forEach.call(demoBtns, function (btn) {
    btn.addEventListener('click', function (event) {
        const parent = event.target.parentElement;
  
      // Toggles the "is-open" class on the demo's parent element.
      parent.classList.toggle('is-open');
    })
  })
}, 3000);
