/* ==================== Toolbar ==================== */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: var(--color-bg-card);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  z-index: 100;
  flex-shrink: 0;
}

.toolbar-left,
.toolbar-center,
.toolbar-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

.toolbar-divider {
  width: 1px;
  height: 24px;
  background: var(--color-border);
  margin: 0 4px;
}

/* ==================== Book Selector ==================== */
.book-selector {
  position: relative;
}

.book-dropdown {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 280px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity 0.15s ease, visibility 0.15s ease, transform 0.15s ease;
  z-index: 200;
}

.book-dropdown.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.book-list {
  max-height: 320px;
  overflow-y: auto;
  padding: 6px;
}

.book-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s ease;
}

.book-item:hover {
  background: var(--color-bg-sidebar);
}

.book-item.active {
  background: var(--color-primary-light);
}

.book-item-title {
  font-weight: 500;
  font-size: 0.9rem;
}

.book-item-author {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.book-dropdown-divider {
  height: 1px;
  background: var(--color-border-light);
  margin: 4px 10px;
}

/* ==================== Theme Switcher ==================== */
.theme-switcher {
  display: flex;
  gap: 2px;
  padding: 3px;
  background: var(--color-bg-sidebar);
  border-radius: 6px;
  border: 1px solid var(--color-border);
}

.theme-btn {
  padding: 5px;
  border-radius: 4px;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.theme-btn.active {
  background: var(--color-bg-card);
  color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

/* ==================== Style Toolbar ==================== */
.style-toolbar {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  background: var(--color-bg-sidebar);
  border-radius: 6px;
  border: 1px solid var(--color-border);
}

.style-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 30px;
  border-radius: 4px;
  color: var(--color-text-secondary);
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.style-btn:hover {
  background: var(--color-bg-card);
  color: var(--color-text);
}

.style-btn.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

/* ==================== Export Menu ==================== */
.export-dropdown {
  position: relative;
}

.export-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 220px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity 0.15s ease, visibility 0.15s ease, transform 0.15s ease;
  z-index: 200;
}

.export-menu.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.export-section {
  padding: 8px;
  border-bottom: 1px solid var(--color-border-light);
}

.export-section:last-child {
  border-bottom: none;
}

.export-section-title {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-muted);
  padding: 6px 10px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.export-item {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 8px 12px;
  border-radius: 6px;
  text-align: left;
  font-size: 0.88rem;
  color: var(--color-text);
  transition: background 0.15s ease;
}

.export-item:hover {
  background: var(--color-bg-sidebar);
}

/* ==================== Main Content ==================== */
.main-content {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ==================== Sidebar ==================== */
.sidebar {
  width: 280px;
  min-width: 260px;
  background: var(--color-bg-sidebar);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  flex-shrink: 0;
}

.sidebar-header {
  padding: 14px 18px;
  border-bottom: 1px solid var(--color-border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sidebar-header h2 {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 600;
}

.nav-tree {
  flex: 1;
  overflow-y: auto;
  padding: 10px;
}

/* ==================== Empty State ==================== */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 20px;
  color: var(--color-text-muted);
  text-align: center;
}

.empty-state svg {
  opacity: 0.4;
  margin-bottom: 14px;
}

.empty-state p {
  font-size: 0.88rem;
}

/* ==================== Tree Nodes ==================== */
.tree-section {
  margin-bottom: 6px;
}

.tree-section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 0;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

.tree-section-toggle {
  cursor: pointer;
  transition: transform 0.15s ease;
  display: flex;
  align-items: center;
}

.tree-section-toggle.collapsed {
  transform: rotate(-90deg);
}

.tree-node {
  position: relative;
}

.tree-node-content {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.15s ease, color 0.15s ease, box-shadow 0.15s ease;
  font-size: 0.88rem;
}

.tree-node-content:hover {
  background: var(--color-primary-light);
}

.tree-node-content.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: 500;
}

.tree-node-content.dragging {
  opacity: 0.5;
}

.tree-node-content.drag-over-top {
  border-top: 2px solid var(--color-primary);
}

.tree-node-content.drag-over-bottom {
  border-bottom: 2px solid var(--color-primary);
}

.tree-node-icon {
  flex-shrink: 0;
  color: var(--color-text-muted);
}

.tree-node-content.active .tree-node-icon {
  color: var(--color-primary);
}

.tree-node-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.tree-node-actions {
  display: none;
  gap: 2px;
}

.tree-node-content:hover .tree-node-actions {
  display: flex;
}

.tree-node-actions button {
  padding: 3px;
  border-radius: 4px;
  color: var(--color-text-muted);
}

.tree-node-actions button:hover {
  background: rgba(0,0,0,0.1);
  color: var(--color-text);
}

.tree-children {
  padding-left: 18px;
}

.tree-children.collapsed {
  display: none;
}

.drag-handle {
  cursor: grab;
  color: var(--color-text-muted);
  opacity: 0.6;
  padding: 2px;
  border-radius: 3px;
}

.tree-node-content:hover .drag-handle {
  opacity: 1;
}

.drag-handle:active {
  cursor: grabbing;
}

/* ==================== Sidebar Font Size ==================== */
.sidebar-large .nav-tree {
  font-size: 1rem;
}

.sidebar-large .tree-node-content {
  padding: 8px 12px;
}

.sidebar-large .tree-node-title {
  font-size: 0.95rem;
}

.sidebar-large .tree-section-header {
  font-size: 0.8rem;
}

.sidebar-large .sidebar-header h2 {
  font-size: 1.1rem;
}

.sidebar-small .nav-tree {
  font-size: 0.85rem;
}

.sidebar-small .tree-node-content {
  padding: 6px 10px;
}

.sidebar-small .tree-node-title {
  font-size: 0.88rem;
}

.sidebar-small .tree-section-header {
  font-size: 0.7rem;
}

.sidebar-small .sidebar-header h2 {
  font-size: 0.95rem;
}

/* ==================== Editor Panel / Paper Container ==================== */
.editor-panel {
  flex: 1;
  overflow: auto;
  background: var(--color-bg);
  padding: 0 24px 24px;
}

.paper-view-container {
  width: 100%;
}

.paper-view-toolbar {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 0;
  padding: 8px 0;
}

.paper-container {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  align-items: flex-start;
  min-height: 100%;
}

.paper-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--color-text-muted);
  text-align: center;
  margin: auto;
}

.paper-placeholder svg {
  opacity: 0.3;
  margin-bottom: 18px;
}

/* ==================== Fullscreen Mode ==================== */
.fullscreen-on .toolbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transform: translateY(-100%);
  transition: transform 0.3s ease;
}

.fullscreen-on .toolbar.visible,
.fullscreen-on .toolbar:hover {
  transform: translateY(0);
}

.fullscreen-on .main-content {
  margin-top: 0;
}

/* ==================== 顶部栏手动开关 ==================== */
/* 隐藏顶部栏：上移出视口，鼠标移到顶部 5px 内可临时唤出 */
.toolbar-hidden .toolbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transform: translateY(-100%);
  transition: transform 0.3s ease;
}
.toolbar-hidden .toolbar.visible,
.toolbar-hidden .toolbar:hover {
  transform: translateY(0);
}
.toolbar-hidden .main-content {
  margin-top: 0 !important;
}

/* ==================== 整页翻模式 ==================== */
/* 开启后：不禁止 overflow（JS 的 scrollTo 仍可工作），由 wheel 的 preventDefault 阻止原生滚动 */
.page-flip-on #paper-container {
  gap: 0;
}

/* ==================== Focus Mode ==================== */
.focus-on .toolbar,
.focus-on .sidebar,
.focus-on .style-toolbar,
.focus-on .paper-view-toolbar,
.focus-on .title-page-toolbar,
.focus-on .preface-settings-bar,
.focus-on .toc-settings-bar,
.focus-on .cover-size-selector {
  opacity: 0.15;
  transition: opacity 0.3s ease;
}

.focus-on .toolbar:hover,
.focus-on .sidebar:hover {
  opacity: 0.8;
}

/* Center paper in focus mode */
.focus-on .editor-panel {
  display: flex;
  justify-content: center;
}

.focus-on .paper-container {
  justify-content: center;
  margin: 0 auto;
}

.focus-on .paper {
  box-shadow: 0 0 40px rgba(0, 0, 0, 0.3);
}

.focus-on .book-text p,
.focus-on .book-text div {
  transition: opacity 0.3s ease;
}

.focus-on .book-text p.dimmed,
.focus-on .book-text div.dimmed {
  opacity: 0.35;
}

.focus-on .book-text p:focus-within,
.focus-on .book-text div:focus-within {
  opacity: 1;
}

.focus-on .chapter-summary,
.focus-on .section-abstract {
  opacity: 0.5;
  transition: opacity 0.3s ease;
}

.focus-on .chapter-summary:focus-within,
.focus-on .section-abstract:focus-within {
  opacity: 1;
}

/* ==================== Active Button States ==================== */
.btn-icon.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

#btn-fullscreen.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

#btn-focus.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

#btn-typewriter.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

#btn-music.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

#btn-phone-read.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

/* ==================== Phone Read Mode（手机阅读模式：在非手机版基准上统一 ×1.5） ==================== */
/* 正文与节/章/序/附录的 book-text 容器（基准 1.3rem ×1.5） */
#app.phone-read-mode .section-page .book-text,
#app.phone-read-mode .chapter-page .book-text,
#app.phone-read-mode .preface-page .book-text,
#app.phone-read-mode .appendix-page .book-text,
#app.phone-read-mode .title-page-content {
  font-size: 1.95rem !important;
  line-height: 1.8 !important;
}
/* 覆盖 pages.css 锁死 <p> 字号的规则（基准 1.3rem ×1.5） */
#app.phone-read-mode .section-page .book-text p,
#app.phone-read-mode .chapter-page .book-text p,
#app.phone-read-mode .preface-page .book-text p,
#app.phone-read-mode .appendix-page .book-text p,
#app.phone-read-mode .title-page-content p {
  font-size: 1.95rem !important;
  line-height: 1.8 !important;
}
/* 节标题/num/name（基准 1.8rem ×1.5）、章标题（基准 2.2rem ×1.5） */
#app.phone-read-mode .section-title,
#app.phone-read-mode .section-title-line .section-num,
#app.phone-read-mode .section-title-line .section-name {
  font-size: 2.7rem !important;
}
#app.phone-read-mode .chapter-title { font-size: 3.3rem !important; }
/* 章编号（基准 1.8rem ×1.5） */
#app.phone-read-mode .chapter-number { font-size: 2.7rem !important; }
/* 小节标题 sub-title（基准 1.15rem ×1.5） */
#app.phone-read-mode .book-text .sub-title { font-size: 1.725rem !important; }
/* 章摘要/节摘要（基准 1.3rem ×1.5） */
#app.phone-read-mode .chapter-summary,
#app.phone-read-mode .section-abstract { font-size: 1.95rem !important; }
/* 页眉页脚（基准 0.85rem ×1.5） */
#app.phone-read-mode .paper-header,
#app.phone-read-mode .paper-footer,
#app.phone-read-mode .page-number { font-size: 1.275rem !important; }
/* 封面 */
#app.phone-read-mode .cover-title { font-size: 3.75rem !important; }
#app.phone-read-mode .cover-subtitle { font-size: 1.95rem !important; }
#app.phone-read-mode .cover-author { font-size: 1.8rem !important; }
/* 版权页 */
#app.phone-read-mode .copyright-page h2 { font-size: 2.25rem !important; }
#app.phone-read-mode .copyright-info p,
#app.phone-read-mode .copyright-info .editable,
#app.phone-read-mode .copyright-bottom { font-size: 1.95rem !important; }
/* 扉页（横排/竖排） */
#app.phone-read-mode .title-page-title { font-size: 3.3rem !important; }
#app.phone-read-mode .title-page-content { font-size: 1.8rem !important; line-height: 2.0 !important; }
#app.phone-read-mode .title-page-content p { font-size: 1.8rem !important; }
#app.phone-read-mode .title-page h1,
#app.phone-read-mode .title-page-horizontal h1 { font-size: 3.0rem !important; }
#app.phone-read-mode .title-author { font-size: 1.8rem !important; }
/* 序 */
#app.phone-read-mode .preface-page h2 { font-size: 2.4rem !important; }
/* 目录（基准 1.3rem ×1.5） */
#app.phone-read-mode .toc-page { font-size: 1.95rem !important; }
#app.phone-read-mode .toc-page .toc-item,
#app.phone-read-mode .toc-page a { font-size: 1.95rem !important; line-height: 2.2 !important; }

/* ==================== User Chip（顶部栏右上角登录标识） ==================== */
.user-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px 4px 5px;
  border-radius: 999px;
  background: var(--color-bg-sidebar);
  border: 1px solid var(--color-border);
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-text);
  line-height: 1;
}
.user-chip:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.user-chip-avatar {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 700;
  flex-shrink: 0;
}
.user-chip-name {
  max-width: 130px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* 目录抽屉开关：桌面隐藏，移动端显示 */
#btn-sidebar-toggle { display: none; }

/* ==================== Responsive ==================== */
@media (min-width: 1800px) {
  .paper-container {
    max-width: none;
  }
}

@media (max-width: 1200px) {
  .toolbar-mode-group {
    display: none;
  }
}

@media (max-width: 900px) {
  .style-toolbar {
    display: none;
  }

  /* 目录改为可收起的抽屉 */
  #btn-sidebar-toggle {
    display: inline-flex;
  }
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 300px;
    min-width: 0;
    max-width: 84vw;
    z-index: 990;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    box-shadow: 0 0 24px rgba(0, 0, 0, 0.18);
  }
  .sidebar-open .sidebar {
    transform: translateX(0);
  }
  .sidebar-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 980;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s ease, visibility 0.2s ease;
  }
  .sidebar-open .sidebar-backdrop {
    opacity: 1;
    visibility: visible;
  }

  /* 纸张按视口等比缩小（zoom 值由 JS updatePaperZoom 写入 --paper-zoom） */
  .paper {
    zoom: var(--paper-zoom, 1);
  }
  .editor-panel {
    padding: 0 10px 16px;
  }
  .paper-container {
    gap: 14px;
  }
}

@media (max-width: 900px) {
  .sidebar {
    width: 240px;
    min-width: 220px;
  }
}

@media (max-width: 600px) {
  .toolbar {
    padding: 8px 10px;
  }
  .toolbar-left,
  .toolbar-right {
    gap: 5px;
  }
  .toolbar-divider {
    display: none;
  }
  /* 小屏收纳低频按钮，保住：目录、书籍切换、主题、全屏、导出、设置、本地文件夹、同步、用户 */
  #btn-delete-book,
  #btn-font-family,
  #btn-undo,
  #btn-redo,
  #btn-toggle-toolbar {
    display: none;
  }
  .btn {
    padding: 6px 9px;
  }
  .btn-icon {
    padding: 6px;
  }
  .btn-export-label {
    display: none;
  }
  .book-dropdown {
    max-width: calc(100vw - 20px);
  }
  .book-item-title {
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  /* 用户徽标在手机上只留头像 */
  .user-chip {
    padding: 4px;
  }
  .user-chip-name {
    display: none;
  }
  .modal-content {
    width: 94%;
  }
  .modal-header {
    padding: 14px 16px;
  }
  .modal-body {
    padding: 14px 16px;
    max-height: 72vh;
  }
  .modal-footer {
    padding: 10px 16px;
  }
}