CSS accordion在单击时打开，但不会关闭！如果能帮上忙，我们将不胜感激

<div class="accordion">
  <div class="accordion-item">
    <div class="accordion-header">面板标题1</div>
    <div class="accordion-content">面板内容1</div>
  </div>
  <div class="accordion-item">
    <div class="accordion-header">面板标题2</div>
    <div class="accordion-content">面板内容2</div>
  </div>
</div>

.accordion-item {
  border: 1px solid #ccc;
}

.accordion-header {
  background-color: #f1f1f1;
  padding: 10px;
  cursor: pointer;
}

.accordion-content {
  padding: 10px;
  display: none;
}

var accordionItems = document.getElementsByClassName('accordion-item');

for (var i = 0; i < accordionItems.length; i++) {
  accordionItems[i].addEventListener('click', function() {
    var content = this.getElementsByClassName('accordion-content')[0];
    if (content.style.display === 'block') {
      content.style.display = 'none';
    } else {
      content.style.display = 'block';
    }
  });
}