/* ════════════════════════════════════════════════════════════════════
   FAQ 折叠面板组件（<details> + <summary>）
   用法：
     <div class="faq-section">
         <div class="container">
             <h2 class="section-heading">...</h2>
             <div class="faq-list">
                 <details>
                     <summary>问题？</summary>
                     <p>回答……</p>
                 </details>
                 ...
             </div>
         </div>
     </div>

   依赖：sheetModal 提供的全局 CSS 变量（可选 — 仅 :root 颜色）。
   动画：由 faq.js 接管 summary 点击 + Web Animations API。
   ════════════════════════════════════════════════════════════════════ */

.faq-section {
    padding: 60px 0;
    background: #f9f9f8;
    border-top: 1px solid #e8e8e8;
}

.faq-list {
    max-width: 780px;
    margin: 40px auto 0;
}

.faq-list details {
    margin-bottom: 10px;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    padding: 16px 20px;
    background: #fff;
}

.faq-list details summary {
    font-weight: 700;
    cursor: pointer;
    color: #222;
    font-size: var(--font-size-16);
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    user-select: none;
    transition: color .2s ease;
}

.faq-list details[open] summary {
    color: var(--clr-primary);
}

@media (hover: hover) and (pointer: fine) {
    .faq-list details summary:hover { color: var(--clr-primary); }
}

.faq-list details summary:active {
    opacity: .7;
}

.faq-list details summary::-webkit-details-marker {
    display: none;
}

.faq-list details summary::after {
    content: '+';
    font-size: var(--font-size-22);
    color: var(--clr-primary);
    flex-shrink: 0;
    margin-left: 12px;
    line-height: 1;
    transition: transform .25s ease;
    display: inline-block;
}

.faq-list details[open] summary::after {
    content: '−';
}

/* 展开/收起动画：JS 在 .faq-body 上做 height 0↔auto 过渡。
   CSS 只负责 overflow 裁剪，动画过程不依赖 [open] 切换。 */
.faq-list details > .faq-body {
    overflow: hidden;
    will-change: height;
}

.faq-list details > .faq-body > p {
    margin: 14px 0 0;
    font-size: var(--font-size-16);
    line-height: 1.85;
    color: #555;
}