:root {
  color-scheme: light dark;
  font-family: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --bg-color: #f7f7f9;
  --text-color: #1f1f24;
  --muted-text: #5f5f6b;
  --border-color: rgba(31, 31, 36, 0.15);
  --accent-color: #4c6ef5;
  --accent-bg: rgba(76, 110, 245, 0.12);
  --header-height: 56px;
  --toc-width: 280px;
  --content-max-width: 920px;
  --transition-fast: 160ms ease;
  --shadow-soft: 0 12px 32px rgba(15, 23, 42, 0.08);
}

@media (min-width: 1200px) {
  :root {
    --content-max-width: 1100px;
  }
}

@media (min-width: 1600px) {
  :root {
    --content-max-width: 1280px;
  }
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg-color);
  color: var(--text-color);
  line-height: 1.66;
}

body.drawer-open {
  overflow: hidden;
}

body.gallery-mode #books-home {
  display: none !important;
}

.app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app-header {
  position: fixed;
  top: 0;
  left: 280px;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 20px;
  height: var(--header-height);
  background: rgba(247, 247, 249, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: left var(--transition-fast);
}

body.gallery-mode .app-header {
  left: 0;
}

.menu-icon-button {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 0;
  margin: 0;
  flex-shrink: 0;
  transition: background var(--transition-fast);
  border-radius: 4px;
}

.menu-icon-button:hover {
  background: rgba(76, 110, 245, 0.1);
}

.menu-icon-button[hidden] {
  display: none;
}

.menu-icon {
  width: 20px;
  height: 20px;
  display: block;
  transition: transform var(--transition-fast);
  color: var(--text-color);
}

.menu-icon-button:hover .menu-icon {
  color: var(--accent-color);
}

.menu-icon-button.collapsed .menu-icon {
  transform: rotate(90deg);
}

body:not(.gallery-mode) .app-header.library-collapsed {
  left: 0;
}

body:not(.gallery-mode) .menu-icon-button {
  display: flex !important;
}

/* 全屏模式样式 */
body.fullscreen-mode {
  overflow: hidden;
  height: 100vh;
}

body.fullscreen-mode .app-header {
  transform: translateY(0);
  transition: transform 0.3s ease;
  /* 全屏模式下默认显示 header，以便用户可以看到退出全屏按钮 */
}

body.fullscreen-mode .app-header.header-hidden {
  transform: translateY(-100%);
  /* 点击内容区域后可以隐藏 header */
}

body.fullscreen-mode .library-sidebar {
  display: none !important;
}

/* 全屏模式下，如果用户点击菜单按钮展开侧边栏，则显示它 */
body.fullscreen-mode .library-sidebar.sidebar-visible-in-fullscreen {
  display: flex !important;
}

body.fullscreen-mode .reader-layout {
  margin-top: 0;
  height: 100vh;
  overflow: hidden;
  display: flex;
}

body.fullscreen-mode .content-wrapper {
  padding-left: 0;
  width: 100%;
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

body.fullscreen-mode .content-area {
  max-width: 100%;
  border-radius: 0;
  margin: 0;
  padding: clamp(20px, 4vw, 32px);
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  flex: 1;
  min-height: 0;
}

/* 全屏模式下大纲保持原样，不改变 */

/* library-sidebar 内容通过 padding-top 从 header 下方开始 */

.app-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 1;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-actions #books-home[hidden] {
  display: none;
}

.book-gallery {
  display: flex;
  flex-direction: column;
  gap: 24px;
  width: 100%;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: clamp(20px, 4vw, 48px);
  padding-top: calc(var(--header-height) + clamp(20px, 4vw, 48px));
  box-sizing: border-box;
}

@media (min-width: 1400px) {
  .book-gallery {
    padding: 48px 72px;
    padding-top: calc(var(--header-height) + 48px);
  }
}

/* 全屏按钮在所有设备上显示 */
.fullscreen-btn {
  display: flex;
}

@media (max-width: 768px) {
  .book-gallery {
    padding: 18px 14px;
    padding-top: calc(var(--header-height) + 40px);
    margin-top: 0;
  }
}

.book-gallery-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.book-gallery-header-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.book-gallery-info {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 12px 0 18px;
}

.book-storage-note {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted-text);
  background: rgba(76, 110, 245, 0.08);
  padding: 8px 12px;
  border-radius: 10px;
}

.book-storage-summary {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0;
  font-size: 0.92rem;
  color: var(--muted-text);
  align-items: center;
}

.book-storage-summary .storage-item {
  background: rgba(76, 110, 245, 0.08);
  padding: 6px 10px;
  border-radius: 999px;
}

.storage-clear {
  margin-left: auto;
}

.book-gallery-header h2 {
  margin: 0;
  font-size: 1.6rem;
  font-weight: 600;
}

.book-gallery-count {
  margin: 0;
  font-size: 0.95rem;
  color: var(--muted-text);
}

.book-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}

@media (min-width: 1280px) {
  .book-list {
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 24px;
  }
}

@media (max-width: 640px) {
  .book-list {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 16px;
  }
}

.book-list.is-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 240px;
}

.book-card {
  border: 1px solid rgba(95, 95, 107, 0.2);
  border-radius: 18px;
  padding: 20px 18px;
  background: rgba(255, 255, 255, 0.85);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
  cursor: pointer;
}

.book-card:hover,
.book-card:focus-visible,
.book-card.active {
  transform: translateY(-4px);
  border-color: rgba(76, 110, 245, 0.35);
  box-shadow: 0 18px 36px rgba(76, 110, 245, 0.18);
  outline: none;
}

.book-card-title {
  margin: 0;
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-color);
}

.book-card-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.book-card-meta {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.92rem;
  color: var(--muted-text);
}

.book-card-tags {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 8px;
}

.book-type-badge,
.book-storage-tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
}

.book-type-badge {
  background: rgba(76, 110, 245, 0.12);
  color: var(--accent-color);
}

.book-storage-tag {
  background: rgba(95, 95, 107, 0.14);
  color: var(--muted-text);
}

.book-card-info {
  font-size: 0.85rem;
  color: var(--muted-text);
}

.book-card-remote {
  font-size: 0.84rem;
  color: rgba(95, 95, 107, 0.6);
}

.book-card-remote.missing {
  font-style: italic;
  color: rgba(95, 95, 107, 0.4);
}

.book-card-remote.syncing {
  color: var(--accent-color);
}

.book-card-remote.error {
  color: #ff6b6b;
}

.book-card-progress {
  position: relative;
  height: 6px;
  border-radius: 999px;
  background: rgba(95, 95, 107, 0.18);
  overflow: hidden;
}

.book-card-progress::after {
  content: "";
  position: absolute;
  inset: 0;
  width: var(--progress, 0%);
  background: linear-gradient(135deg, #63e6be 0%, #37b24d 100%);
  transition: width 220ms ease;
}

.book-card-footer {
  margin-top: 4px;
}

.book-card-actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  margin-top: 12px;
}

.book-card-actions .icon-button {
  width: 40px;
  height: 40px;
  min-width: 40px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(95, 95, 107, 0.25);
  background: rgba(247, 247, 249, 0.8);
  border-radius: 8px;
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  transition: border-color var(--transition-fast), color var(--transition-fast), background var(--transition-fast);
}

.book-card-actions .icon-button:hover,
.book-card-actions .icon-button:focus-visible {
  border-color: var(--accent-color);
  color: var(--accent-color);
  background: var(--accent-bg);
  outline: none;
}

.book-card-actions .book-delete {
  color: #ff6b6b;
  border-color: rgba(255, 107, 107, 0.3);
}

.book-card-actions .book-delete:hover,
.book-card-actions .book-delete:focus-visible {
  border-color: #ff6b6b;
  color: #ff6b6b;
  background: rgba(255, 107, 107, 0.1);
  outline: none;
}

.book-card-status {
  font-size: 0.85rem;
  color: var(--muted-text);
}

.book-card-empty {
  border: 1px dashed rgba(95, 95, 107, 0.35);
  border-radius: 16px;
  padding: 28px;
  text-align: center;
  color: rgba(95, 95, 107, 0.6);
  background: rgba(255, 255, 255, 0.7);
}

/* 占位卡片样式 */
.book-card.placeholder {
  opacity: 0.85;
  border-style: dashed;
  border-color: rgba(76, 110, 245, 0.4);
  background: rgba(76, 110, 245, 0.05);
  cursor: default;
}

.book-card.placeholder:hover {
  transform: none;
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
}

.book-card.placeholder .book-card-title {
  position: relative;
}

.book-card.placeholder .book-card-title::after {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  margin-left: 8px;
  border: 2px solid var(--accent-color);
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  vertical-align: middle;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* 错误状态样式 */
.book-card.error-state {
  border-color: rgba(255, 107, 107, 0.4);
  background: rgba(255, 107, 107, 0.05);
}

.book-card.error-state .book-card-status {
  color: #ff6b6b;
  font-weight: 500;
}

.book-card.error-state .book-card-remote.error {
  color: #ff6b6b;
  font-weight: 500;
}

/* 检查更新和同步状态样式 */
.book-card-remote.checking {
  color: var(--accent-color);
  position: relative;
  padding-left: 16px;
}

.book-card-remote.checking::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 10px;
  height: 10px;
  border: 2px solid var(--accent-color);
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.book-card-remote.up-to-date {
  color: #37b24d;
}

.book-card-remote.syncing {
  color: var(--accent-color);
  font-weight: 500;
}

/* 重试按钮样式 */
.book-card-actions .book-retry {
  color: var(--accent-color);
  border-color: rgba(76, 110, 245, 0.3);
}

.book-card-actions .book-retry:hover,
.book-card-actions .book-retry:focus-visible {
  border-color: var(--accent-color);
  color: var(--accent-color);
  background: var(--accent-bg);
  outline: none;
}

/* 表单错误提示样式 */
.form-error {
  display: block;
  color: #ff6b6b;
  font-size: 0.85rem;
  margin-top: 8px;
  padding: 8px 12px;
  background: rgba(255, 107, 107, 0.1);
  border-radius: 6px;
  border-left: 3px solid #ff6b6b;
}

/* 复选框标签样式 */
.checkbox-label {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  font-weight: 500;
  margin-bottom: 0;
}

.checkbox-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin: 0;
  cursor: pointer;
  accent-color: var(--accent-color);
  flex-shrink: 0;
}

.checkbox-label span {
  flex: 1;
  user-select: none;
}

.checkbox-label:hover input[type="checkbox"] {
  opacity: 0.8;
}

.panel-toggle-group {
  display: inline-flex;
  background: rgba(76, 110, 245, 0.08);
  border-radius: 999px;
  padding: 4px;
  gap: 4px;
}

.panel-toggle-button {
  border: none;
  background: transparent;
  color: var(--muted-text);
  padding: 6px 16px;
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.panel-toggle-button:hover,
.panel-toggle-button:focus-visible {
  background: rgba(76, 110, 245, 0.16);
  color: var(--accent-color);
  outline: none;
}

.panel-toggle-button.active {
  background: var(--accent-color);
  color: #fff;
}

.font-size-control {
  display: flex;
  align-items: center;
  gap: 4px;
}

.icon-button {
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.85);
  color: var(--text-color);
  padding: 6px 10px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.icon-button:hover {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.icon-button:focus-visible {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
  outline: none;
}

.icon-button:active {
  transform: scale(0.95);
}

.icon-button:focus:not(:focus-visible) {
  outline: none;
  background: rgba(255, 255, 255, 0.85);
  border-color: var(--border-color);
  color: var(--text-color);
}

.icon-button {
  user-select: none;
  -webkit-user-select: none;
}

#help-btn {
  width: 32px;
  height: 32px;
  min-width: 32px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-weight: 600;
  font-size: 1.1rem;
  background: var(--accent-bg);
  color: var(--accent-color);
  border-color: var(--accent-color);
}

#help-btn:hover,
#help-btn:focus-visible {
  background: var(--accent-color);
  color: white;
  transform: scale(1.05);
}

.panel-action[hidden] {
  display: none;
}

.panel-views {
  display: flex;
  flex-direction: column;
  gap: 16px;
  height: 100%;
}

.panel-view {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.95rem;
  min-height: 0;
}

.panel-view.hidden {
  display: none;
}

.panel-view[data-panel="library"] {
  flex: 1;
}

.file-tree {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
  overflow-y: auto;
  min-height: 0;
  width: 100%;
}

.tree-item {
  display: block;
  list-style: none;
}

.tree-node {
  width: 100%;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 10px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted-text);
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
  font: inherit;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
  padding-left: calc(12px + var(--depth, 0) * 16px);
}

.tree-node:focus-visible {
  background: var(--accent-bg);
  color: var(--accent-color);
  border-color: var(--accent-color);
  outline: none;
}

/* 移除 hover 时的选中效果，只在真正打开文件时才选中 */
.tree-node:hover {
  background: rgba(76, 110, 245, 0.05);
  /* 不改变文字颜色和边框，保持默认样式 */
}

.tree-node.active {
  background: rgba(0, 0, 0, 0.05) !important;
  border-color: transparent !important;
  border-width: 1px !important;
  box-shadow: none !important;
  /* 灰色背景 + 蓝色文字 */
}

.tree-node.active .file-title {
  color: var(--accent-color) !important;
  font-weight: 600;
}

/* 确保 active 状态在 hover 时也保持 */
.tree-node.active:hover {
  background: rgba(0, 0, 0, 0.08) !important;
  border-color: transparent !important;
}

.tree-node.active:hover .file-title {
  color: var(--accent-color) !important;
}

.tree-node.directory-node {
  font-weight: 600;
}

.tree-node.directory-node .tree-label {
  flex: 1;
  margin-right: 6px;
}

.directory-progress-text {
  font-size: 0.78rem;
  color: rgba(95, 95, 107, 0.55);
  margin-right: 6px;
}

/* 文件夹完成状态：保持默认文字颜色，不显示蓝色，避免与选中状态混淆 */
.tree-node.directory-node[data-aggregate-state="completed"] .tree-label,
.tree-node.directory-node[data-aggregate-state="completed"] .directory-progress-text {
  color: var(--text-color);
  /* 不再使用 var(--accent-color)，避免与文件选中状态混淆 */
}

/* 确保文件夹即使有 completed 状态，也不会有 active 的背景高亮 */
.tree-node.directory-node.active {
  background: transparent !important;
  border-color: transparent !important;
  color: inherit !important;
  box-shadow: none !important;
}

.tree-node.directory-node.active .tree-label {
  color: var(--accent-color) !important;
}

.tree-node.directory-node.is-empty {
  cursor: default;
}

.tree-node.directory-node.is-empty:hover,
.tree-node.directory-node.is-empty:focus-visible {
  background: transparent;
  color: var(--muted-text);
  border-color: transparent;
}

.tree-caret {
  width: 12px;
  height: 12px;
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast), color var(--transition-fast);
}

.file-icon-placeholder {
  width: 12px;
  height: 12px;
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.tree-caret::before {
  content: "";
  border-style: solid;
  border-width: 4px 0 4px 6px;
  border-color: transparent transparent transparent var(--muted-text);
  transform-origin: center;
}

.tree-item.directory.expanded > .tree-node .tree-caret {
  transform: rotate(90deg);
}

.tree-node.active .tree-caret::before {
  border-color: transparent transparent transparent var(--accent-color);
}

.tree-node.is-empty .tree-caret::before {
  opacity: 0;
}

.tree-children {
  list-style: none;
  margin: 0;
  padding: 0;
}

.tree-children[hidden] {
  display: none;
}

.file-list-placeholder {
  color: var(--muted-text);
  font-size: 0.9rem;
  padding: 8px 4px;
  border-radius: 6px;
}

.tree-node .file-title {
  display: block;
  font-weight: 600;
  margin-bottom: 0;
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.progress-indicator {
  position: relative;
  flex: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--bg-color) 62%, transparent 64%);
  box-shadow: inset 0 0 0 1.5px rgba(95, 95, 107, 0.35);
  transition: box-shadow var(--transition-fast);
}

.progress-indicator::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: conic-gradient(
    rgba(95, 95, 107, 0.55) 0deg,
    rgba(95, 95, 107, 0.55) var(--progress, 0deg),
    rgba(95, 95, 107, 0) var(--progress, 0deg),
    rgba(95, 95, 107, 0) 360deg
  );
  mask: radial-gradient(circle, transparent 61%, #000 63%);
  -webkit-mask: radial-gradient(circle, transparent 61%, #000 63%);
  opacity: 0;
  transition: background var(--transition-fast), opacity var(--transition-fast);
}

.progress-indicator[data-state="in-progress"]::after {
  opacity: 1;
  background: conic-gradient(#3bc87f 0deg, #3bc87f var(--progress, 0deg), transparent var(--progress, 0deg), transparent 360deg);
  mask: radial-gradient(circle, transparent 56%, #000 60%);
  -webkit-mask: radial-gradient(circle, transparent 56%, #000 60%);
  box-shadow: inset 0 0 0 2px rgba(59, 200, 127, 0.2), 0 0 4px rgba(59, 200, 127, 0.35);
}

.progress-indicator[data-state="completed"] {
  box-shadow: inset 0 0 0 2px #37b24d, 0 0 5px rgba(55, 178, 77, 0.4);
}

.progress-indicator[data-state="completed"]::after {
  opacity: 1;
  background: conic-gradient(#37b24d 360deg, transparent 360deg);
}

.progress-indicator .progress-check {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.68rem;
  font-weight: 600;
  color: #0b5d3b;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.progress-indicator[data-state="completed"] .progress-check {
  opacity: 1;
}


.toc-panel a {
  color: var(--muted-text);
  text-decoration: none;
  display: block;
  padding: 6px 8px;
  border-radius: 6px;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.toc-panel a:hover,
.toc-panel a:focus-visible {
  background: var(--accent-bg);
  color: var(--accent-color);
  outline: none;
}

.toc-panel a.active {
  color: var(--accent-color);
  background: var(--accent-bg);
  font-weight: 600;
}

.toc-item {
  margin-left: calc((var(--level) - 1) * 14px);
}

.reader {
  flex: 1;
  display: flex;
  justify-content: center;
  padding: 32px clamp(16px, 4vw, 48px);
}

.reader:has(.reader-layout) {
  padding: 0;
}

.reader-layout {
  display: flex;
  width: 100%;
  max-width: 100%;
  gap: 0;
  min-height: 100vh;
  margin: 0;
  padding: 0;
  position: relative;
  margin-top: 0;
}

body.gallery-mode .library-sidebar {
  position: relative;
  left: auto;
  top: auto;
  height: auto;
  z-index: auto;
}

body.gallery-mode .content-wrapper {
  margin-left: 0;
}

.library-sidebar {
  width: 280px;
  min-width: 280px;
  background: rgba(255, 255, 255, 0.96);
  border-radius: 0;
  box-shadow: none;
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: width var(--transition-fast), min-width var(--transition-fast), margin var(--transition-fast);
  position: fixed;
  left: 0;
  top: var(--header-height);
  height: calc(100vh - var(--header-height));
  z-index: 10;
}

/* library-sidebar-header 已移除 */

/* library-sidebar-toggle 已移至 header，样式在 .menu-icon-button 中 */

.library-sidebar.collapsed {
  width: 0;
  min-width: 0;
  overflow: hidden;
  margin-right: 0;
}

.library-sidebar.collapsed .tree-toolbar {
  display: none;
}

body:not(.gallery-mode) .library-sidebar.collapsed ~ .content-wrapper,
body:not(.gallery-mode) .library-sidebar.collapsed ~ * .content-wrapper {
  margin-left: 0;
}

.library-sidebar-expand {
  position: fixed;
  left: 0;
  top: calc(var(--header-height) + 32px);
  width: 40px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  border-left: none;
  background: rgba(255, 255, 255, 0.96);
  border-radius: 0 8px 8px 0;
  cursor: pointer;
  z-index: 15;
  transition: background var(--transition-fast);
  box-shadow: var(--shadow-soft);
}

.library-sidebar-expand:hover {
  background: var(--accent-bg);
}

.library-sidebar-expand[hidden] {
  display: none;
}

body.gallery-mode .library-sidebar-expand {
  display: none;
}

.library-sidebar-expand .menu-icon {
  width: 20px;
  height: 16px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: stretch;
}

.library-sidebar-expand .menu-icon-line {
  width: 100%;
  height: 2px;
  background: var(--text-color);
  border-radius: 1px;
  transition: all var(--transition-fast);
}

.library-sidebar-expand:hover .menu-icon-line {
  background: var(--accent-color);
}

.library-sidebar-title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-color);
}

.library-sidebar-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 0;
  margin: 0;
  height: 100%;
  position: relative;
}

.tree-toolbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 280px;
  height: var(--header-height);
  padding: 0;
  margin: 0;
  border: none;
  background: transparent;
  box-sizing: border-box;
  z-index: 101;
  display: flex;
  align-items: center;
}

.tree-toolbar-button {
  position: relative;
  left: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  margin: 0;
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.85);
  color: var(--text-color);
  border-radius: 6px;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
  user-select: none;
  -webkit-user-select: none;
}

.tree-toolbar-button:hover {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.tree-toolbar-button:focus-visible {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
  outline: none;
}

.tree-toolbar-button:active {
  transform: scale(0.95);
}

.tree-toolbar-icon {
  width: 16px;
  height: 16px;
  display: block;
  color: var(--text-color);
  transition: color var(--transition-fast);
}

.tree-toolbar-button:hover .tree-toolbar-icon {
  color: var(--accent-color);
}

.library-list {
  flex: 1;
  overflow-y: auto;
  list-style: none;
  margin: 0;
  padding: 0;
  padding-top: 32px;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.library-book-item {
  display: flex;
  flex-direction: column;
}

.library-book-tree {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.content-wrapper {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  position: relative;
  padding-left: 24px;
  margin-left: 280px;
  transition: margin-left var(--transition-fast);
}

.outline-toggle-button {
  position: fixed;
  left: 300px;
  top: calc(var(--header-height) + 16px);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.96);
  border-radius: 8px;
  cursor: pointer;
  font: inherit;
  color: var(--text-color);
  transition: left var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
  box-shadow: var(--shadow-soft);
  z-index: 15;
}

body:not(.gallery-mode) .app-header.library-collapsed ~ * .outline-toggle-button,
body:not(.gallery-mode) .app-header.library-collapsed ~ .outline-toggle-button {
  left: 20px;
}

body.gallery-mode .outline-toggle-button {
  display: none;
}

.outline-toggle-button:hover,
.outline-toggle-button:focus-visible {
  background: var(--accent-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
  outline: none;
}

.outline-toggle-icon {
  font-size: 1.1rem;
}

.outline-toggle-text {
  font-weight: 500;
}

.outline-overlay {
  position: fixed;
  left: 300px;
  top: calc(var(--header-height) + 16px);
  width: 320px;
  max-height: calc(100vh - var(--header-height) - 36px);
  background: rgba(255, 255, 255, 0.98);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.15);
  z-index: 100;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  backdrop-filter: blur(12px);
  pointer-events: auto;
  transition: left var(--transition-fast);
}

body:not(.gallery-mode) .app-header.library-collapsed ~ * .outline-overlay,
body:not(.gallery-mode) .app-header.library-collapsed ~ .outline-overlay {
  left: 20px;
}

.outline-overlay[hidden] {
  display: none;
}

.outline-overlay-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(247, 247, 249, 0.94);
}

.outline-overlay-title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-color);
}

.outline-close-button {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  cursor: pointer;
  color: var(--muted-text);
  font-size: 1.5rem;
  line-height: 1;
  transition: color var(--transition-fast);
  border-radius: 4px;
}

.outline-close-button:hover {
  color: var(--accent-color);
  background: rgba(76, 110, 245, 0.1);
}

.outline-overlay .toc-panel {
  flex: 1;
  overflow-y: auto;
  padding: 16px 20px;
  max-height: calc(100vh - var(--header-height) - 180px);
}

.theme-dark .outline-toggle-button {
  background: rgba(18, 20, 27, 0.96);
  border-color: var(--border-color);
}

.theme-dark .outline-toggle-button:hover,
.theme-dark .outline-toggle-button:focus-visible {
  background: var(--accent-bg);
  border-color: var(--accent-color);
}

.theme-dark .outline-overlay {
  background: rgba(18, 20, 27, 0.98);
}

.theme-dark .outline-overlay-header {
  background: rgba(24, 27, 36, 0.94);
}

.theme-dark .library-sidebar-expand {
  background: rgba(18, 20, 27, 0.96);
}

.content-area {
  flex: 1;
  width: 100%;
  max-width: var(--content-max-width);
  background: rgba(255, 255, 255, 0.96);
  border-radius: 16px;
  padding: clamp(24px, 5vw, 48px);
  box-shadow: var(--shadow-soft);
  box-sizing: border-box;
  margin: 0 auto;
}

.content-area h1,
.content-area h2,
.content-area h3,
.content-area h4,
.content-area h5,
.content-area h6 {
  position: relative;
  scroll-margin-top: calc(var(--header-height) + 12px);
  margin-top: 2.2em;
  margin-bottom: 0.75em;
  font-weight: 600;
}

.content-area h1 {
  font-size: clamp(2rem, 3vw, 2.6rem);
}

.content-area h2 {
  font-size: clamp(1.6rem, 2.5vw, 2.1rem);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.4em;
}

.content-area h3 {
  font-size: clamp(1.35rem, 2vw, 1.7rem);
}

.content-area p {
  margin: 1em 0;
  letter-spacing: 0.01em;
}

.content-area a {
  color: var(--accent-color);
  text-decoration: none;
}

.content-area a:hover,
.content-area a:focus-visible {
  text-decoration: underline;
  outline: none;
}

.content-area pre {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 12px;
  padding: 16px;
  overflow-x: auto;
  font-family: "JetBrains Mono", "Fira Code", "SFMono-Regular", Menlo, monospace;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* Markdown 中代码块的语法高亮样式 */
.content-area pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  border-radius: 0;
  font-size: inherit;
}

/* highlight.js 的样式已经通过 highlight.min.css 引入，这里只做必要的覆盖 */
/* 如果需要自定义颜色，可以在这里添加，但通常 highlight.js 的默认样式已经足够好了 */

.content-area code {
  background: rgba(15, 23, 42, 0.08);
  border-radius: 6px;
  padding: 2px 6px;
  font-family: "JetBrains Mono", "Fira Code", "SFMono-Regular", Menlo, monospace;
  font-size: 0.92rem;
}

.content-area blockquote {
  margin: 1.5em 0;
  padding: 12px 16px;
  border-left: 4px solid var(--accent-color);
  background: rgba(76, 110, 245, 0.08);
  border-radius: 8px;
  color: var(--muted-text);
}

.content-area ul,
.content-area ol {
  margin: 1em 0;
  padding-left: 1.6em;
}

.content-area table {
  width: 100%;
  border-collapse: collapse;
  margin: 2em 0;
  font-size: 0.95rem;
}

.content-area th,
.content-area td {
  border: 1px solid var(--border-color);
  padding: 12px 16px;
  text-align: left;
}

.content-area th {
  background: rgba(76, 110, 245, 0.12);
  color: var(--accent-color);
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  border-radius: 999px;
  padding: 12px 16px;
  box-shadow: var(--shadow-soft);
  display: none;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--transition-fast), transform var(--transition-fast);
  z-index: 200;
}

.back-to-top.visible {
  display: inline-flex !important;
  opacity: 1 !important;
  transform: translateY(0) !important;
}

body.gallery-mode .back-to-top {
  display: none !important;
}

.drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  backdrop-filter: blur(6px);
  z-index: 30;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.drawer-overlay.visible {
  opacity: 1;
  pointer-events: auto;
}

.drawer {
  position: fixed;
  top: 0;
  left: 0;
  width: min(90vw, 360px);
  max-width: 360px;
  height: 100vh;
  background: rgba(247, 247, 249, 0.96);
  border-right: 1px solid var(--border-color);
  box-shadow: var(--shadow-soft);
  transform: translateX(-100%);
  transition: transform var(--transition-fast);
  z-index: 40;
  display: flex;
  flex-direction: column;
}

.drawer.visible {
  transform: translateX(0);
}

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
  background: rgba(247, 247, 249, 0.94);
}

.drawer-title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 600;
}

.drawer-content {
  flex: 1;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.drawer-panel {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
}

.drawer-panel.hidden {
  display: none;
}

.toc-panel {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.95rem;
  padding: 16px;
  box-sizing: border-box;
  background: rgba(247, 247, 249, 0.5);
  border-radius: 8px;
}

/* 暗色主题 */
.theme-dark {
  --bg-color: #12141b;
  --text-color: #f1f5f9;
  --muted-text: #cbd5f5;
  --border-color: rgba(226, 232, 240, 0.14);
  --accent-bg: rgba(96, 165, 250, 0.28);
  --shadow-soft: 0 12px 32px rgba(15, 23, 42, 0.35);
}

.theme-dark body {
  background: var(--bg-color);
  color: var(--text-color);
}

.theme-dark .app-header,
.theme-dark .content-area,
.theme-dark .library-sidebar {
  background: rgba(18, 20, 27, 0.92);
}

.theme-dark .library-sidebar-header {
  background: rgba(24, 27, 36, 0.92);
}

.theme-dark .toc-panel {
  background: rgba(24, 27, 36, 0.5);
}

.theme-dark .icon-button {
  background: rgba(30, 34, 45, 0.9);
}

.theme-dark .content-area code {
  background: rgba(148, 163, 184, 0.2);
}

/* 响应式适配 */
@media (max-width: 1080px) {
  .reader {
    padding: 24px clamp(12px, 5vw, 32px);
  }

  .book-gallery {
    padding: clamp(20px, 6vw, 36px);
    padding-top: calc(var(--header-height) + clamp(20px, 6vw, 36px));
  }

  .book-list {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }

  .content-area {
    border-radius: 12px;
    padding: clamp(20px, 6vw, 36px);
  }

  .reader-layout {
    gap: 16px;
  }

  .library-sidebar {
    width: 240px;
    min-width: 240px;
  }
}

@media (max-width: 680px) {
  .app-header {
    gap: 8px;
    padding: 0 12px;
  }

  .app-title {
    font-size: 1rem;
  }

  .header-actions {
    gap: 6px;
  }

  .panel-toggle-group {
    gap: 2px;
  }

  .panel-toggle-button {
    padding: 6px 12px;
  }

  .icon-button {
    padding: 6px 8px;
    border-radius: 6px;
    font-size: 0.85rem;
    min-height: 36px;
  }
}

/* 模态框样式 */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  opacity: 0;
  transition: opacity var(--transition-fast);
  pointer-events: none;
}

.modal-overlay:not([hidden]) {
  opacity: 1;
  pointer-events: auto;
}

.modal-overlay[hidden] {
  display: none !important;
}

.modal-content {
  background: var(--bg-color);
  border-radius: 12px;
  box-shadow: var(--shadow-soft);
  width: 90%;
  max-width: 600px;
  max-height: 90vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transform: scale(0.95);
  transition: transform var(--transition-fast);
}

.modal-overlay:not([hidden]) .modal-content {
  transform: scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
}

.modal-title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 600;
}

.modal-body {
  padding: 24px 24px;
  overflow-y: auto;
}

@media (min-width: 500px) {
  .modal-body {
    padding: 24px 48px;
  }
}

.form-group {
  margin-bottom: 20px;
  width: 100%;
  box-sizing: border-box;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--text-color);
  width: 100%;
  box-sizing: border-box;
}

.form-group input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-color);
  color: var(--text-color);
  font-size: 0.95rem;
  font-family: inherit;
  transition: border-color var(--transition-fast);
  box-sizing: border-box;
}

.form-group input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px var(--accent-bg);
}

.form-hint {
  display: block;
  margin-top: 6px;
  font-size: 0.85rem;
  color: var(--muted-text);
  width: 100%;
  box-sizing: border-box;
  line-height: 1.5;
}

.form-hint .hint-icon {
  display: inline-block;
  margin-right: 6px;
  font-size: 1em;
  vertical-align: middle;
}

.form-actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  margin-top: 24px;
}

.button-primary,
.button-secondary {
  padding: 10px 20px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
}

.button-primary {
  background: var(--accent-color);
  color: white;
}

.button-primary:hover {
  background: #3d5ae8;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(76, 110, 245, 0.3);
}

.button-secondary {
  background: transparent;
  color: var(--text-color);
  border: 1px solid var(--border-color);
}

.button-secondary:hover {
  background: var(--border-color);
}

.theme-dark .modal-overlay {
  background: rgba(0, 0, 0, 0.7);
}

.theme-dark .modal-content {
  background: rgba(24, 27, 36, 0.95);
}

.theme-dark .form-group input {
  background: rgba(30, 34, 45, 0.9);
  border-color: rgba(148, 163, 184, 0.2);
}

.theme-dark .button-secondary {
  border-color: rgba(148, 163, 184, 0.2);
}

.form-group input.input-error {
  border-color: #ff6b6b;
  box-shadow: 0 0 0 3px rgba(255, 107, 107, 0.15);
}

/* 书库空状态样式 */
.book-list-empty {
  font-size: 1.05rem;
  color: var(--muted-text);
  line-height: 1.7;
  margin: 0 auto;
  padding: 56px 16px;
  max-width: 420px;
  text-align: center;
}

/* 单选项样式 */
.radio-option {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-right: 18px;
  font-weight: 500;
  color: var(--text-color);
}

.radio-option input[type="radio"] {
  width: 16px;
  height: 16px;
  cursor: pointer;
  accent-color: var(--accent-color);
}

.radio-option span {
  user-select: none;
}

/* 代码查看器 */
.code-viewer {
  margin: 0;
  padding: 20px;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 12px;
  overflow-x: auto;
  font-family: "JetBrains Mono", "Fira Code", "SFMono-Regular", Menlo, monospace;
  font-size: 0.92rem;
  line-height: 1.6;
  max-height: 70vh;
  white-space: pre;
}

.code-viewer code {
  display: block;
  white-space: pre;
  background: transparent !important;
  color: #e2e8f0 !important;
  padding: 0 !important;
  border-radius: 0 !important;
  font-size: inherit !important;
  font-family: inherit !important;
}

/* 确保代码高亮样式优先级最高 */
.code-viewer code .hljs-comment,
.code-viewer .hljs-comment { 
  color: #8b949e !important; 
  font-style: italic; 
}
.code-viewer code .hljs-keyword,
.code-viewer .hljs-keyword { 
  color: #ff7b72 !important; 
}
.code-viewer code .hljs-string,
.code-viewer .hljs-string { 
  color: #a5d6ff !important; 
}
.code-viewer code .hljs-number,
.code-viewer .hljs-number { 
  color: #f2cc60 !important; 
}
.code-viewer code .hljs-literal,
.code-viewer .hljs-literal { 
  color: #79c0ff !important; 
}
.code-viewer code .hljs-attr,
.code-viewer .hljs-attr { 
  color: #d2a8ff !important; 
}
.code-viewer code .hljs-tag,
.code-viewer .hljs-tag { 
  color: #ffa657 !important; 
}
.code-viewer code .hljs-selector,
.code-viewer .hljs-selector { 
  color: #79c0ff !important; 
}
.code-viewer code .hljs-variable,
.code-viewer .hljs-variable { 
  color: #ffa657 !important; 
}
.code-viewer code .hljs-attr-value,
.code-viewer .hljs-attr-value { 
  color: #a5d6ff !important; 
}
.code-viewer code .hljs-link,
.code-viewer .hljs-link { 
  color: #a5d6ff !important; 
}