自定CSS逼ま手琖琴（一般看问题答案）

<div class="accordion-container">
  <details class="accordion" name="faq">
    <summary class="accordion-summary">
      这个手风琴的特点是什么？
      <span class="icon"></span>
    </summary>
    <div class="accordion-content">
      <p>不使用JavaScript，仅用HTML标准功能和CSS构建。非常轻量，且在SEO和无障碍访问（如支持键盘操作）方面也非常优秀。</p>
    </div>
  </details>
  
  <details class="accordion" name="faq">
    <summary class="accordion-summary">
      可以同时打开多个项目吗？
      <span class="icon"></span>
    </summary>
    <div class="accordion-content">
      <p>通过将name属性设置为相同的值，可以实现互斥控制（打开一个时另一个关闭）。</p>
    </div>
  </details>
</div>

/* 容器的样式 */
.accordion-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
}

/* 手风琴主体 */
.accordion {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background-color: #ffffff;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

/* 摘要（标题）的样式 */
.accordion-summary {
  padding: 1.25rem 1.5rem;
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none; /* 隐藏默认的三角形标记 */
  color: #1e293b;
  transition: background-color 0.2s ease;
  user-select: none;
}

/* 面向Safari的默认三角形标记隐藏 */
.accordion-summary::-webkit-details-marker {
  display: none;
}

.accordion-summary:hover {
  background-color: #f8fafc;
}

/* 打开状态下摘要的下划线 */
.accordion[open] .accordion-summary {
  border-bottom: 1px solid #e2e8f0;
}

/* 开闭图标的样式 */
.icon {
  position: relative;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-left: 1rem;
}

/* 图标的横线和竖线 */
.icon::before,
.icon::after {
  content: '';
  position: absolute;
  background-color: #64748b;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 2px;
}

.icon::before {
  width: 16px;
  height: 2px;
}

.icon::after {
  width: 2px;
  height: 16px;
}

/* 手风琴打开时的动画（＋变成－） */
.accordion[open] .icon::after {
  transform: rotate(90deg) scaleY(0);
}

.accordion[open] .icon::before {
  background-color: #3b82f6;
}

/* 内容部分的样式 */
.accordion-content {
  padding: 1.5rem;
  color: #475569;
  line-height: 1.6;
  animation: fadeDown 0.3s ease-out forwards;
}

.accordion-content p {
  margin: 0;
}

/* 柔和显示的动画 */
@keyframes fadeDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}