/* ============================================================
   layout_L2.css — 长文型变体 L2「左侧目录型」专属布局层
   ------------------------------------------------------------
   配套渲染函数：layout_engine.render_L2_top_toc()
   输出结构（DOM不变，CSS将TOC从顶部改为左侧栏）：
     <div class="l2-wrap container">
       <div class="main-content">
         <div class="l2-toc">...</div>
         {body}
       </div>
     </div>
   颜色/字体/圆角全部继承 seo_global.css 变量，零硬编码。
   ============================================================ */

.l2-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 24px;
}

/* 主内容区：grid布局，左侧TOC + 右侧正文 */
.l2-wrap .main-content {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  align-items: start;
  min-width: 0;
}

/* 目录卡：左侧固定，滚动时sticky悬浮 */
.l2-toc {
  grid-column: 1;
  background: var(--blue-50);
  border: 1px solid var(--gray-200);
  border-radius: 12px;
  padding: 20px 18px;
  position: sticky;
  top: 120px;
  align-self: start;
}

.l2-toc h3 {
  font-size: 14px;
  font-weight: 800;
  color: var(--gray-900);
  margin-bottom: 12px;
}

/* 目录项：单列 */
.l2-toc ol {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: l2toc;
}

.l2-toc li {
  counter-increment: l2toc;
  font-size: 13px;
  margin-bottom: 8px;
}

.l2-toc li::before {
  content: counter(l2toc);
  display: inline-flex;
  width: 20px;
  height: 20px;
  background: var(--blue);
  color: var(--white);
  border-radius: 50%;
  font-size: 11px;
  font-weight: 700;
  align-items: center;
  justify-content: center;
  margin-right: 8px;
  vertical-align: middle;
}

.l2-toc a {
  color: var(--gray-700);
  text-decoration: none;
  line-height: 1.5;
}

.l2-toc a:hover {
  color: var(--blue);
}

/* 正文区占右侧 */
.l2-wrap .main-content > :not(.l2-toc) {
  grid-column: 2;
  min-width: 0;
}

/* 正文区内标题/段落样式 */
.l2-wrap .main-content h2 {
  font-size: 22px; font-weight: 700; color: var(--gray-900);
  margin: 28px 0 14px; padding-bottom: 8px;
  border-bottom: 2px solid var(--brand);
}
.l2-wrap .main-content h3 { font-size: 17px; font-weight: 700; margin: 22px 0 10px; color: var(--gray-900); }
.l2-wrap .main-content p  { margin-bottom: 14px; }
.l2-wrap .main-content ul, .l2-wrap .main-content ol { padding-left: 20px; margin-bottom: 14px; }
.l2-wrap .main-content li { margin-bottom: 6px; }

/* 响应式：移动端TOC回到顶部单列 */
@media (max-width: 768px) {
  .l2-wrap .main-content {
    grid-template-columns: 1fr;
  }
  .l2-toc {
    position: static;
    grid-column: 1;
  }
  .l2-wrap .main-content > :not(.l2-toc) {
    grid-column: 1;
  }
  .l2-toc ol {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6px 16px;
  }
}