/* ========================================
   详情页专用样式 v5 — 根rem流式缩放
   所有尺寸用rem，随根字号自动缩放
   ======================================== */

/* 详情页 Header */
.detail-header {
  background: linear-gradient(135deg, var(--gradient-start) 0%, var(--primary) 50%, var(--primary-light) 100%);
  padding: 6rem 0 3rem;
  margin-top: var(--header-h);
  color: #fff;
  position: relative;
  overflow: hidden;
}

.detail-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 10% 20%, rgba(21, 114, 204, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 90% 80%, rgba(86, 165, 232, 0.12) 0%, transparent 50%);
}

.detail-header .container {
  position: relative;
  z-index: 2;
}

.breadcrumb {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.8rem;
}

.breadcrumb a { color: var(--accent-light); }
.breadcrumb a:hover { color: #fff; }
.breadcrumb span { margin: 0 0.4rem; opacity: 0.5; }

.detail-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  margin-bottom: 0.4rem;
}

.detail-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
}

/* ========================================
   详情页主体布局
   ======================================== */
.detail-layout {
  display: flex;
  gap: 2.5rem;
  max-width: 82rem;
  margin: 2.5rem auto;
  padding: 0 var(--container-pad);
  align-items: flex-start;
}

/* 右侧章节导航 */
.detail-side-nav {
  width: 12rem;
  flex-shrink: 0;
  position: sticky;
  top: calc(var(--header-h) + 0.75rem);
}

.chapter-nav-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.8rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent-light);
}

.chapter-nav-list { list-style: none; }

.chapter-nav-list li { margin-bottom: 0.2rem; }

.chapter-nav-list a {
  display: block;
  padding: 0.45rem 0.8rem;
  font-size: 0.85rem;
  color: var(--text-gray);
  border-radius: 0.375rem;
  border-left: 2px solid transparent;
  transition: var(--transition);
  line-height: 1.5;
}

.chapter-nav-list a:hover {
  background: #f3f8fd;
  color: var(--primary);
  border-left-color: var(--accent);
}

.chapter-nav-list a.active {
  background: linear-gradient(90deg, #e8f1fa, transparent);
  color: var(--primary);
  font-weight: 600;
  border-left-color: var(--accent);
  padding-left: 1rem;
}

/* 左侧内容区 */
.detail-main { flex: 1; min-width: 0; }

/* PDF 预览模式 */
.pdf-viewer {
  background: #e8e8e8;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  min-height: 50rem;
  position: relative;
}

.pdf-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 1.2rem;
  background: #333;
  color: #ccc;
  font-size: 0.85rem;
}

.pdf-toolbar-left {
  display: flex; align-items: center;
  gap: 0.6rem;
}

.pdf-page-info {
  background: rgba(255,255,255,0.1);
  padding: 0.25rem 0.6rem;
  border-radius: 4px;
}

.pdf-actions button {
  background: rgba(255,255,255,0.15);
  border: none; color: #ddd;
  padding: 0.3rem 0.7rem;
  border-radius: 4px; cursor: pointer;
  font-size: 0.8rem;
  transition: var(--transition);
}

.pdf-actions button:hover {
  background: rgba(255,255,255,0.25);
  color: #fff;
}

.pdf-canvas-area {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 1.5rem;
  min-height: 45rem;
  background: #525659;
}

.pdf-placeholder {
  text-align: center;
  color: rgba(255,255,255,0.5);
  padding: 4rem 1.5rem;
}

.pdf-placeholder-icon {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  opacity: 0.4;
}

/* 图片展示模式（PDF转图） */
.image-viewer {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-light);
  overflow: hidden;
}

.image-viewer img { width: 100%; display: block; }

.page-indicator {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 0.8rem;
  background: #f8f9fa;
  border-top: 1px solid #eee;
}

.page-btn {
  width: 2.5rem; height: 2.5rem;
  border-radius: 50%;
  border: 1px solid #ddd;
  background: #fff; cursor: pointer;
  font-size: 1rem;
  display: flex; align-items: center; justify-content: center;
  transition: var(--transition);
}

.page-btn:hover:not(:disabled) {
  background: var(--accent); color: #fff;
  border-color: var(--accent);
}

.page-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.page-number {
  font-size: 0.85rem;
  color: var(--text-gray);
  font-variant-numeric: tabular-nums;
}

/* 内容展示模式 */
.content-viewer {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-light);
  padding: 3rem 3.5rem;
  line-height: 2;
  font-size: 1rem;
  color: var(--text-dark);
}

.content-viewer h2 {
  font-size: 1.6rem;
  color: var(--primary);
  margin-top: 2rem;
  margin-bottom: 0.8rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid #eee;
}

.content-viewer h2:first-child { margin-top: 0; }

.content-viewer h3 {
  font-size: 1.25rem;
  color: var(--primary-dark);
  margin-top: 1.5rem;
  margin-bottom: 0.6rem;
}

.content-viewer p {
  margin-bottom: 0.8rem;
  text-indent: 2em;
  text-align: justify;
}

.content-viewer table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

.content-viewer table th,
.content-viewer table td {
  border: 1px solid #ddd;
  padding: 0.5rem 0.75rem;
  text-align: left;
}

.content-viewer table th {
  background: #f5f7fa;
  font-weight: 700;
  color: var(--primary);
}

.content-viewer ul,
.content-viewer ol {
  margin: 0.5rem 0 0.8rem 2em;
}

.content-viewer li {
  margin-bottom: 0.4rem;
  line-height: 1.8;
}

.content-viewer blockquote {
  margin: 1.2rem 0;
  padding: 0.8rem 1.5rem;
  background: #f3f8fd;
  border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-gray);
  font-style: italic;
  font-size: 0.9rem;
}

.content-viewer .figure {
  margin: 1.5rem 0;
  text-align: center;
}

.content-viewer .figure img {
  max-width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow-light);
  margin-bottom: 0.6rem;
}

.content-viewer .figure-caption {
  font-size: 0.8rem;
  color: var(--text-gray);
}

/* 返回按钮 */
.back-bar {
  max-width: 82rem;
  margin: 1.5rem auto 0;
  padding: 0 var(--container-pad);
}

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1.3rem;
  background: var(--bg-white);
  border: 1px solid #ddd;
  border-radius: 1.5rem;
  color: var(--text-gray);
  font-size: 0.85rem;
  transition: var(--transition);
}

.back-btn:hover {
  background: var(--primary); color: #fff;
  border-color: var(--primary);
}

/* ========================================
   详情页 — 布局切换断点（仅布局，不调字号）
   ======================================== */

/* 平板端：章节导航移到顶部 */
@media (max-width: 1024px) {
  .detail-layout { flex-direction: column; }

  .detail-side-nav {
    width: 100%;
    position: static;
    order: -1;
  }

  .chapter-nav-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  .chapter-nav-list li { margin-bottom: 0; }

  .chapter-nav-list a {
    border-left: none;
    border-bottom: 2px solid transparent;
    white-space: nowrap;
  }

  .chapter-nav-list a.active {
    border-left: none;
    border-bottom-color: var(--accent);
    padding-left: 0.8rem;
  }

  .chapter-nav-title { display: none; }
}

/* 移动端：章节导航横向滚动 */
@media (max-width: 768px) {
  .chapter-nav-list {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 0.25rem;
  }
  .chapter-nav-list::-webkit-scrollbar { display: none; }

  .content-viewer { padding: 1.5rem; }

  /* 表格横向滚动 */
  .content-viewer .table-wrap,
  .content-viewer table {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}

/* 触摸设备优化 */
@media (hover: none) and (pointer: coarse) {
  .page-btn { width: 2.75rem; height: 2.75rem; }
  .chapter-nav-list a { min-height: 2.75rem; display: flex; align-items: center; }
  .back-btn { min-height: 2.75rem; }
}

/* 安全区域适配 */
@supports (padding-top: env(safe-area-inset-top)) {
  .detail-header {
    padding-top: calc(6rem + env(safe-area-inset-top));
  }
}