參考：Bootstrap(中)、w3schools(英)、RUNOOB(中)

Collapse折疊面板的設計

<!-- #accordion 的 Collapse 設計 -->
<div id="accordion">
 
  <!-- 第一組 =============================================== -->
  <div class="card">
    <div class="card-header">
      <a class="card-link" data-toggle="collapse" href="#collapseOne">
        Collapsible Group Item #1111
      </a>
    </div>
    <div id="collapseOne" class="collapse show" data-parent="#accordion">
      <div class="card-body">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
      </div>
    </div>
  </div>
  
  <!-- 第二組 =============================================== -->
  <div class="card">
    <div class="card-header">
      <a class="collapsed card-link" data-toggle="collapse" href="#collapseTwo">
      Collapsible Group Item #2222
    </a>
    </div>
    <div id="collapseTwo" class="collapse" data-parent="#accordion">
      <div class="card-body">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
      </div>
    </div>
  </div>
  
  <!-- 第三組 =============================================== -->
  <div class="card">
    <div class="card-header">
      <a class="collapsed card-link" data-toggle="collapse" href="#collapseThree">
        Collapsible Group Item #3333
      </a>
    </div>
    <div id="collapseThree" class="collapse" data-parent="#accordion">
      <div class="card-body">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
      </div>
    </div>
  </div>
  
</div>