/* ============================================
 * 电子书模块样式
 * ============================================ */

/* ----- 布局 ----- */
.ebook-layout {
  display: flex;
  min-height: calc(100vh - var(--header-height, 64px) - 80px);
  padding-top: var(--header-height, 64px);
}

/* ----- 左侧目录面板 ----- */
.ebook-sidebar {
  width: 280px;
  min-width: 280px;
  background: var(--surface-primary);
  border-right: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  position: sticky;
  top: var(--header-height, 64px);
  height: calc(100vh - var(--header-height, 64px));
  overflow: hidden;
  transition: width var(--transition-base), min-width var(--transition-base), transform var(--transition-base);
  z-index: 10;
}

.ebook-sidebar.collapsed {
  width: 0;
  min-width: 0;
  border-right: none;
  overflow: hidden;
}

.ebook-sidebar-header {
  padding: 20px 20px 12px;
  border-bottom: 1px solid var(--border-light);
  flex-shrink: 0;
}

.ebook-selector {
  margin-bottom: 12px;
}

.ebook-selector select {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  background: var(--surface-secondary);
  color: var(--text-primary);
  font-size: 0.9rem;
  cursor: pointer;
  outline: none;
  transition: all var(--transition-fast);
}

.ebook-selector select:hover {
  border-color: var(--color-sage);
}

.ebook-selector select:focus {
  border-color: var(--color-sage);
  box-shadow: 0 0 0 3px rgba(106, 141, 109, 0.15);
}

.ebook-sidebar-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-deep);
  margin-bottom: 2px;
}

.ebook-sidebar-edition {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.ebook-sidebar-progress {
  margin-top: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.ebook-progress-bar {
  flex: 1;
  height: 4px;
  background: var(--surface-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.ebook-progress-fill {
  height: 100%;
  background: var(--color-sage);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
}

.ebook-progress-text {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  white-space: nowrap;
}

/* 目录列表 */
.ebook-toc {
  flex: 1;
  overflow-y: auto;
  padding: 8px 0;
}

.ebook-toc::-webkit-scrollbar {
  width: 4px;
}

.ebook-toc::-webkit-scrollbar-thumb {
  background: var(--border-default);
  border-radius: var(--radius-full);
}

/* 篇 */
.ebook-toc-part {
  margin-bottom: 4px;
}

.ebook-toc-part-title {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-deep);
  cursor: pointer;
  transition: background-color var(--transition-fast);
  user-select: none;
}

.ebook-toc-part-title:hover {
  background: var(--surface-secondary);
}

.ebook-toc-part-arrow {
  font-size: 0.65rem;
  transition: transform var(--transition-base);
  color: var(--text-muted);
  flex-shrink: 0;
}

.ebook-toc-part.expanded .ebook-toc-part-arrow {
  transform: rotate(90deg);
}

/* 章 */
.ebook-toc-chapters {
  display: none;
}

.ebook-toc-part.expanded .ebook-toc-chapters {
  display: block;
}

.ebook-toc-chapter {
  position: relative;
}

.ebook-toc-chapter-title {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px 8px 32px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  position: relative;
}

.ebook-toc-chapter-title::before {
  content: '';
  position: absolute;
  left: 22px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--border-light);
}

.ebook-toc-chapter-title:hover {
  background: var(--surface-secondary);
  color: var(--color-deep);
}

.ebook-toc-chapter-title.active {
  color: var(--color-sage);
  background: rgba(90, 125, 92, 0.06);
  font-weight: 600;
}

.ebook-toc-chapter-arrow {
  font-size: 0.6rem;
  transition: transform var(--transition-base);
  color: var(--text-muted);
  flex-shrink: 0;
}

.ebook-toc-chapter.expanded .ebook-toc-chapter-arrow {
  transform: rotate(90deg);
}

/* 小节 */
.ebook-toc-sections {
  display: none;
}

.ebook-toc-chapter.expanded .ebook-toc-sections {
  display: block;
}

.ebook-toc-section {
  position: relative;
}

.ebook-toc-section-title {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 20px 6px 46px;
  font-size: 0.78rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  position: relative;
}

.ebook-toc-section-title::before {
  content: '';
  position: absolute;
  left: 36px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--border-light);
}

.ebook-toc-section-title:hover {
  background: var(--surface-secondary);
  color: var(--text-secondary);
}

.ebook-toc-section-title.active {
  color: var(--color-sage);
  background: rgba(90, 125, 92, 0.06);
  font-weight: 600;
}

/* 已读标记 */
.ebook-toc-read-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-sage);
  flex-shrink: 0;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.ebook-toc-section-title.read .ebook-toc-read-dot {
  opacity: 1;
}

/* 书签标记 */
.ebook-toc-bookmark-icon {
  font-size: 0.65rem;
  color: var(--color-amber);
  flex-shrink: 0;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.ebook-toc-section-title.bookmarked .ebook-toc-bookmark-icon {
  opacity: 1;
}

/* ----- 右侧阅读区域 ----- */
.ebook-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* 工具栏 */
.ebook-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 32px;
  background: var(--surface-primary);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: var(--header-height, 64px);
  z-index: 9;
  flex-wrap: wrap;
}

.ebook-toolbar-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.ebook-toolbar-toggle:hover {
  background: var(--surface-secondary);
  color: var(--color-deep);
}

.ebook-toolbar-breadcrumb {
  font-size: 0.82rem;
  color: var(--text-muted);
  flex: 1;
  min-width: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.ebook-toolbar-breadcrumb span {
  color: var(--text-secondary);
}

.ebook-toolbar-breadcrumb .current {
  color: var(--color-deep);
  font-weight: 500;
}

.ebook-toolbar-actions {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.ebook-toolbar-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 34px;
  padding: 0 12px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.ebook-toolbar-btn:hover {
  background: var(--surface-secondary);
  color: var(--color-deep);
  border-color: var(--border-default);
}

.ebook-toolbar-btn.active {
  background: rgba(90, 125, 92, 0.08);
  color: var(--color-sage);
  border-color: var(--color-sage);
}

.ebook-toolbar-btn svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* 搜索框 */
.ebook-search-wrapper {
  position: relative;
}

.ebook-search-input {
  height: 34px;
  padding: 0 12px 0 32px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  background: var(--surface-primary);
  color: var(--text-primary);
  font-size: 0.82rem;
  width: 180px;
  transition: all var(--transition-fast);
  outline: none;
}

.ebook-search-input:focus {
  border-color: var(--color-sage);
  box-shadow: 0 0 0 3px rgba(90, 125, 92, 0.1);
  width: 240px;
}

.ebook-search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.ebook-search-icon svg {
  width: 14px;
  height: 14px;
}

/* 搜索结果下拉 */
.ebook-search-results {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
  min-width: 320px;
  background: var(--surface-primary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  max-height: 360px;
  overflow-y: auto;
  display: none;
  z-index: 50;
}

.ebook-search-results.visible {
  display: block;
}

.ebook-search-result-item {
  padding: 10px 16px;
  cursor: pointer;
  transition: background-color var(--transition-fast);
  border-bottom: 1px solid var(--border-light);
}

.ebook-search-result-item:last-child {
  border-bottom: none;
}

.ebook-search-result-item:hover {
  background: var(--surface-secondary);
}

.ebook-search-result-title {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.ebook-search-result-preview {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.ebook-search-result-item mark {
  background: rgba(90, 125, 92, 0.2);
  color: inherit;
  padding: 0 1px;
  border-radius: 2px;
}

.ebook-search-empty {
  padding: 20px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* 字号控制 */
.ebook-font-controls {
  display: flex;
  align-items: center;
  gap: 4px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.ebook-font-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 0.85rem;
  font-weight: 600;
}

.ebook-font-btn:hover {
  background: var(--surface-secondary);
  color: var(--color-deep);
}

.ebook-font-size-label {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  padding: 0 4px;
  min-width: 28px;
  text-align: center;
}

/* ----- 阅读内容区 ----- */
.ebook-content {
  flex: 1;
  padding: 40px 48px 60px;
  max-width: 860px;
  width: 100%;
  margin: 0 auto;
}

.ebook-content[data-font-size="small"] {
  font-size: 0.9rem;
}

.ebook-content[data-font-size="medium"] {
  font-size: 1rem;
}

.ebook-content[data-font-size="large"] {
  font-size: 1.12rem;
}

.ebook-content[data-font-size="xlarge"] {
  font-size: 1.24rem;
}

/* 空状态 */
.ebook-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 400px;
  text-align: center;
}

.ebook-empty-icon {
  margin-bottom: 16px;
  opacity: 0.4;
}

.ebook-empty-icon svg {
  width: 64px;
  height: 64px;
  color: var(--color-olive);
}

.ebook-empty-text {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.ebook-empty-hint {
  font-size: 0.85rem;
  color: var(--text-muted);
  opacity: 0.7;
}

/* 章节标题 */
.ebook-section-header {
  margin-bottom: 28px;
  animation: fadeInUp 0.4s ease;
}

.ebook-section-part {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-sage);
  margin-bottom: 6px;
}

.ebook-section-title {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--color-deep);
  margin-bottom: 8px;
  line-height: 1.3;
}

.ebook-section-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* 内容正文 */
.ebook-section-body {
  animation: fadeInUp 0.4s ease;
}

.ebook-section-content {
  line-height: 1.8;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.ebook-section-content p {
  margin-bottom: 16px;
  text-indent: 2em;
}

.ebook-section-content p:first-child {
  text-indent: 0;
}

/* 核心考点卡片 */
.ebook-key-points {
  margin-bottom: 32px;
}

.ebook-key-points-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-deep);
  margin-bottom: 14px;
}

.ebook-key-points-title svg {
  width: 18px;
  height: 18px;
  color: var(--color-amber);
}

.ebook-key-point-card {
  background: #fdf8ed;
  border: 1px solid #f0e4c8;
  border-left: 4px solid var(--color-amber);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  margin-bottom: 10px;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
  transition: box-shadow var(--transition-fast);
}

.ebook-key-point-card:hover {
  box-shadow: var(--shadow-sm);
}

/* 关联知识点 */
.ebook-related {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border-light);
}

.ebook-related-title {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.ebook-related-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.ebook-related-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 500;
  background: rgba(90, 125, 92, 0.08);
  color: var(--color-sage);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.ebook-related-tag:hover {
  background: rgba(90, 125, 92, 0.16);
  color: var(--color-mid);
}

.ebook-related-tag svg {
  width: 12px;
  height: 12px;
  flex-shrink: 0;
}

/* 增强的关联知识点标签：分类色 + 内部结构 */
.ebook-related-tag {
  padding: 5px 11px 5px 9px;
  gap: 6px;
  flex-direction: row-reverse;
}

.ebook-related-tag-cat {
  font-size: 0.66rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: var(--radius-full, 999px);
  background: rgba(255, 255, 255, 0.55);
  color: inherit;
  opacity: 0.85;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.ebook-related-tag-name {
  font-size: 0.78rem;
  font-weight: 500;
  line-height: 1.2;
}

/* 按学科分类着色（与 knowledge-graph.js 配色保持一致） */
.ebook-related-tag.cat-cell      { background: rgba(90, 123, 196, 0.12);  color: #3a5ba4; }
.ebook-related-tag.cat-cell:hover{ background: rgba(90, 123, 196, 0.22);  color: #2a4a94; }
.ebook-related-tag.cat-molbio    { background: rgba(138, 106, 196, 0.12); color: #6a4aa4; }
.ebook-related-tag.cat-molbio:hover{ background: rgba(138, 106, 196, 0.22); color: #5a3a94; }
.ebook-related-tag.cat-biochem   { background: rgba(196, 154, 74, 0.14);  color: #a47a2a; }
.ebook-related-tag.cat-biochem:hover{ background: rgba(196, 154, 74, 0.24); color: #845a1a; }
.ebook-related-tag.cat-genetics  { background: rgba(196, 122, 74, 0.12);  color: #a45a2a; }
.ebook-related-tag.cat-genetics:hover{ background: rgba(196, 122, 74, 0.22); color: #844a1a; }
.ebook-related-tag.cat-zoology   { background: rgba(196, 90, 122, 0.12);  color: #a43a5a; }
.ebook-related-tag.cat-zoology:hover{ background: rgba(196, 90, 122, 0.22); color: #842a4a; }
.ebook-related-tag.cat-botany    { background: rgba(90, 170, 90, 0.12);   color: #3a8a3a; }
.ebook-related-tag.cat-botany:hover{ background: rgba(90, 170, 90, 0.22); color: #2a7a2a; }
.ebook-related-tag.cat-micro     { background: rgba(74, 170, 196, 0.12);  color: #2a8aa4; }
.ebook-related-tag.cat-micro:hover{ background: rgba(74, 170, 196, 0.22); color: #1a7a94; }
.ebook-related-tag.cat-eco       { background: rgba(74, 156, 106, 0.12);  color: #2a7c4a; }
.ebook-related-tag.cat-eco:hover { background: rgba(74, 156, 106, 0.22);  color: #1a6c3a; }
.ebook-related-tag.cat-misc      { background: rgba(90, 125, 92, 0.08);   color: var(--color-sage); }
.ebook-related-tag.cat-misc:hover{ background: rgba(90, 125, 92, 0.16);   color: var(--color-mid); }

/* 夜间模式适配：分类色降低亮度、提升对比 */
.ebook-night-mode .ebook-related-tag-cat { background: rgba(0, 0, 0, 0.25); opacity: 0.9; }
.ebook-night-mode .ebook-related-tag.cat-cell     { background: rgba(90, 123, 196, 0.22);  color: #8aacde; }
.ebook-night-mode .ebook-related-tag.cat-molbio   { background: rgba(138, 106, 196, 0.22); color: #ac8ade; }
.ebook-night-mode .ebook-related-tag.cat-biochem  { background: rgba(196, 154, 74, 0.24);  color: #dcb066; }
.ebook-night-mode .ebook-related-tag.cat-genetics { background: rgba(196, 122, 74, 0.22);  color: #dc9466; }
.ebook-night-mode .ebook-related-tag.cat-zoology  { background: rgba(196, 90, 122, 0.22);  color: #dc6a8a; }
.ebook-night-mode .ebook-related-tag.cat-botany   { background: rgba(90, 170, 90, 0.22);   color: #7ace7a; }
.ebook-night-mode .ebook-related-tag.cat-micro    { background: rgba(74, 170, 196, 0.22);  color: #6abace; }
.ebook-night-mode .ebook-related-tag.cat-eco      { background: rgba(74, 156, 106, 0.22);  color: #6ab48a; }

/* 底部导航 */
.ebook-section-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
}

.ebook-nav-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  background: var(--surface-primary);
  color: var(--text-secondary);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  max-width: 45%;
}

.ebook-nav-btn:hover {
  border-color: var(--color-sage);
  color: var(--color-sage);
  background: rgba(90, 125, 92, 0.04);
}

.ebook-nav-btn svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.ebook-nav-btn-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.ebook-nav-btn-text {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 书签按钮（阅读区内） */
.ebook-bookmark-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--text-muted);
  font-size: 0.78rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: 20px;
}

.ebook-bookmark-btn:hover {
  border-color: var(--color-amber);
  color: var(--color-amber);
}

.ebook-bookmark-btn.active {
  background: rgba(196, 149, 106, 0.1);
  border-color: var(--color-amber);
  color: var(--color-amber);
}

.ebook-bookmark-btn svg {
  width: 14px;
  height: 14px;
}

.ebook-pdf-btn {
  margin-left: 8px;
  border-color: rgba(59, 130, 246, 0.3);
  color: #3b82f6;
}

.ebook-pdf-btn:hover {
  background: rgba(59, 130, 246, 0.1);
  border-color: #3b82f6;
  color: #2563eb;
}

/* ----- 书签侧边栏 ----- */
.ebook-bookmarks-panel {
  position: fixed;
  top: var(--header-height, 64px);
  right: 0;
  width: 320px;
  height: calc(100vh - var(--header-height, 64px));
  background: var(--surface-primary);
  border-left: 1px solid var(--border-light);
  box-shadow: var(--shadow-lg);
  z-index: 20;
  transform: translateX(100%);
  transition: transform var(--transition-base);
  display: flex;
  flex-direction: column;
}

.ebook-bookmarks-panel.visible {
  transform: translateX(0);
}

.ebook-bookmarks-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-light);
}

.ebook-bookmarks-title {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-deep);
}

.ebook-bookmarks-close {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.ebook-bookmarks-close:hover {
  background: var(--surface-secondary);
  color: var(--text-primary);
}

.ebook-bookmarks-list {
  flex: 1;
  overflow-y: auto;
  padding: 8px;
}

.ebook-bookmark-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.ebook-bookmark-item:hover {
  background: var(--surface-secondary);
}

.ebook-bookmark-item-icon {
  color: var(--color-amber);
  flex-shrink: 0;
  margin-top: 2px;
}

.ebook-bookmark-item-icon svg {
  width: 14px;
  height: 14px;
}

.ebook-bookmark-item-info {
  flex: 1;
  min-width: 0;
}

.ebook-bookmark-item-title {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.ebook-bookmark-item-meta {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.ebook-bookmark-item-remove {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
  opacity: 0;
  transition: all var(--transition-fast);
}

.ebook-bookmark-item:hover .ebook-bookmark-item-remove {
  opacity: 1;
}

.ebook-bookmark-item-remove:hover {
  background: rgba(192, 85, 58, 0.08);
  color: var(--color-error);
}

.ebook-bookmarks-empty {
  padding: 40px 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ----- 阅读统计 ----- */
.ebook-stats-bar {
  display: flex;
  gap: 16px;
  padding: 12px 32px;
  background: var(--surface-secondary);
  border-bottom: 1px solid var(--border-light);
  flex-wrap: wrap;
}

.ebook-stat-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.ebook-stat-value {
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--color-sage);
}

/* ----- 夜间模式 ----- */
.ebook-night-mode .ebook-sidebar {
  background: var(--surface-primary);
}

.ebook-night-mode .ebook-content {
  color: var(--text-secondary);
}

.ebook-night-mode .ebook-key-point-card {
  background: rgba(196, 149, 106, 0.08);
  border-color: rgba(196, 149, 106, 0.2);
  border-left-color: var(--color-amber);
}

/* ----- 响应式 ----- */
/* 移动端侧边栏遮罩 */
.ebook-sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  top: var(--header-height, 64px);
  background: rgba(0, 0, 0, 0.4);
  z-index: 40;
  transition: opacity var(--transition-base);
}

@media (max-width: 1024px) {
  .ebook-sidebar-overlay.visible {
    display: block;
  }

  .ebook-content {
    padding: 32px 28px 48px;
  }

  .ebook-sidebar {
    position: fixed;
    left: 0;
    top: var(--header-height, 64px);
    height: calc(100vh - var(--header-height, 64px));
    width: 280px;
    min-width: 280px;
    box-shadow: var(--shadow-lg);
    transform: translateX(-100%);
    z-index: 50;
    transition: transform var(--transition-base);
  }

  .ebook-sidebar:not(.collapsed) {
    transform: translateX(0);
  }
}

@media (max-width: 768px) {
  .ebook-toolbar {
    padding: 10px 16px;
    gap: 6px;
  }

  .ebook-search-input {
    width: 120px;
  }

  .ebook-search-input:focus {
    width: 160px;
  }

  .ebook-content {
    padding: 24px 16px 40px;
  }

  .ebook-section-title {
    font-size: 1.4rem;
  }

  .ebook-toolbar-breadcrumb {
    display: none;
  }

  .ebook-stats-bar {
    padding: 10px 16px;
    gap: 10px;
  }

  .ebook-section-nav {
    flex-direction: column;
  }

  .ebook-nav-btn {
    max-width: 100%;
  }

  .ebook-bookmarks-panel {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .ebook-toolbar-btn span {
    display: none;
  }

  .ebook-toolbar-btn {
    padding: 0 8px;
  }

  .ebook-font-size-label {
    display: none;
  }
}