/* ═══════════════════════════════════════════════
   变量与基础 —— 采用第二份的配色系统
═══════════════════════════════════════════════ */
:root {
  --bg: #f7f5f0;
  --bg-sidebar: #efede8;
  --bg-card: #ffffff;
  --bg-hover: #e8e4dd;
  --bg-active: #dfd9cf;
  --border: #d8d2c8;
  --border-light: #e8e4dd;
  --text: #1c1917;
  --text-2: #57534e;
  --text-3: #a8a29e;
  --accent: #b45309;
  --accent-2: #92400e;
  --accent-bg: #fef3c7;
  --link: #1d4ed8;
  --link-hover: #1e40af;
  --code-bg: #f0ece4;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, .08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, .10);
  --nav-h: 52px;
  --sidebar-w: 340px;
  --sidebar-r: 260px;
  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, 
             "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", 
             sans-serif;
  
  /* 正文衬线字体 - 中文优先思源宋体/宋体 */
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", 
                Georgia, "Times New Roman", serif;
  
  /* 正文字体（无衬线版本，如果需要） */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", 
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", 
               "Noto Sans SC", sans-serif;
  
  /* 等宽字体 - 包含中文等宽回退 */
  --font-mono: "SF Mono", SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
               "Noto Sans Mono CJK SC", "PingFang SC", "Microsoft YaHei Mono", 
               "Courier New", monospace;
  /* 注意：删除 --font-serif 等字体变量，让前面 CSS 控制字体 */
}
[data-theme="dark"] {
  --bg: #141210;
  --bg-sidebar: #1c1917;
  --bg-card: #1c1917;
  --bg-hover: #282420;
  --bg-active: #312e29;
  --border: #2c2824;
  --border-light: #242018;

  --text: #e7e5e0;
  --text-2: #a8a29e;
  --text-3: #57534e;
  --text-inv: #1c1917;

  --accent: #f59e0b;
  --accent-2: #fbbf24;
  --accent-bg: #1c1505;
  --accent-border: #78350f;

  --link: #60a5fa;
  --link-hover: #93c5fd;

  --code-bg: #242018;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, .3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, .4);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-padding-top: calc(var(--nav-h) + 24px);
}

body {
  background: var(--bg) !important;
  color: var(--text) !important;
  /* 删除 font-family 和 line-height，让前面 CSS 控制 */
}


/* 进度条 */
#progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0%;
  background: var(--accent);
  z-index: 1000;
  transition: width 80ms linear;
}

/* ═══════════════════════════════════════════════
   导航栏
═══════════════════════════════════════════════ */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-h);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  z-index: 300;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] #navbar {
  background: rgba(28, 27, 25, 0.95);
  border-bottom-color: var(--border);
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

#nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.3px;
}

#nav-logo img {
  width: 28px;
  height: 28px;
  border-radius: 4px;
}

#nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
#navbar,
#nav-tree,
.nav-section-header,
.nav-group-header,
.nav-item,
#toc-list,
.toc-item,
#mobile-menu,
.mobile-menu-item,
#sidebar-toggle,
.nav-btn,
.font-btn {
  font-family: var(--font-ui) !important;
}

/* 更细粒度的菜单项控制，确保中文显示正常 */
.nav-section-header {
  font-family: var(--font-ui) !important;
  font-weight: 600;
  /* 中文需要略细一点的字重，避免700太粗 */
  letter-spacing: 0.05em;
  /* 中文字间距不宜过大 */
}

.nav-item,
.toc-item {
  font-family: var(--font-ui) !important;
  /* 中文菜单项行高需要更大 */
  line-height: 1.6;
}
.desktop-tools {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 字号控制组：A- [滑块] A+ */
.font-control-group {
  display: flex;
  align-items: center;
  gap: 2px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 2px;
  height: 32px;
}

.font-btn {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--text-2);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  transition: all 150ms;
  font-size: 13px;
  font-weight: 600;
  font-family: var(--font-sans);
}

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

/* 滑块样式 —— 第二份风格 */
input[type="range"] {
  -webkit-appearance: none;
  width: 80px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
  margin: 0 4px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid white;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  transition: transform 150ms ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

/* 功能按钮（书签、主题） */
.nav-btn {
  width: 32px;
  height: 32px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: transparent;
  color: var(--text-3);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 150ms;
  flex-shrink: 0;
}

.nav-btn:hover {
  background: var(--bg-hover);
  color: var(--text-2);
}

.nav-btn.active {
  color: var(--accent);
  background: var(--accent-bg);
  border-color: var(--accent-border);
}

/* 搜索框 */
#search-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0 10px;
  height: 32px;
  width: 200px;
  transition: all 150ms;
  position: relative;
}

#search-bar:focus-within {
  border-color: var(--accent);
  background: var(--bg-card);
  width: 240px;
}

#search-bar input {
  background: none;
  border: none;
  outline: none;
  font-size: 13px;
  color: var(--text);
  width: 100%;
  font-family: var(--font-sans);
}

#search-bar input::placeholder {
  color: var(--text-3);
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
  display: none;
  width: 32px;
  height: 32px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: transparent;
  color: var(--text-3);
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

/* ═══════════════════════════════════════════════
   移动端下拉菜单
═══════════════════════════════════════════════ */
#mobile-menu {
  display: none;
  position: fixed;
  top: calc(var(--nav-h) + 6px);
  right: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  box-shadow: var(--shadow-md);
  z-index: 310;
  min-width: 220px;
  padding: 12px 0;
  opacity: 0;
  transform: translateY(-10px) scale(0.98);
  transition: opacity 200ms, transform 200ms;
  pointer-events: none;
}

#mobile-menu.visible {
  display: block;
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

.mobile-menu-header {
  padding: 0 16px 8px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-3);
  letter-spacing: 0.08em;
}

.mobile-font-slider-wrapper {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px 16px;
}

.font-adjust-btn {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text-2);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 16px;
}

#mobile-font-slider {
  flex: 1;
  height: 4px;
}

.mobile-divider {
  height: 1px;
  background: var(--border-light);
  margin: 8px 0;
}

.mobile-menu-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  font-size: 14px;
  color: var(--text);
  cursor: pointer;
  transition: background 150ms;
}

.mobile-menu-item:hover {
  background: var(--bg-hover);
}

.mobile-menu-item .toggle-indicator {
  font-size: 10px;
  color: var(--accent);
  font-weight: 700;
}

/* ═══════════════════════════════════════════════
   侧边栏 —— 细滚动条版本（第二份风格）
═══════════════════════════════════════════════ */
#sidebar-backdrop {
  display: none;
  position: fixed;
  top: var(--nav-h);
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.25);
  z-index: 250;
  backdrop-filter: blur(2px);
  opacity: 0;
  transition: opacity 300ms;
}

#sidebar-backdrop.visible {
  display: block;
  opacity: 1;
}

#shell {
  display: flex;
  min-height: 100vh;
  position: relative;
}

/* 左侧边栏 —— 4px 细滚动条 */
#lsidebar {
  position: fixed;
  left: 0;
  top: var(--nav-h);
  width: var(--sidebar-w);
  height: calc(100vh - var(--nav-h));
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  overflow-x: hidden;
  z-index: 260;
  transform: translateX(-100%);
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1);

  /* 细滚动条核心 */
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

#lsidebar.open {
  transform: translateX(0);
  box-shadow: 4px 0 24px rgba(0, 0, 0, 0.12);
}

/* Webkit 细滚动条（4px） */
#lsidebar::-webkit-scrollbar {
  width: 4px;
}

#lsidebar::-webkit-scrollbar-track {
  background: transparent;
}

#lsidebar::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

#lsidebar::-webkit-scrollbar-thumb:hover {
  background: var(--text-3);
}

[data-theme="dark"] #lsidebar::-webkit-scrollbar-thumb {
  background: var(--border);
}

[data-theme="dark"] #lsidebar::-webkit-scrollbar-thumb:hover {
  background: var(--text-2);
}

/* 导航树容器 */
#nav-tree {
  padding: 8px 0;
}

/* 一级：文集标题（如 LENIN · ZH） */
.nav-section {
  margin-bottom: 2px;
}
.nav-section-items,
.nav-group-items {
  display: none;
}

.nav-section.open>.nav-section-items,
.nav-group.open>.nav-group-items {
  display: block;
}

.nav-section-header .chevron,
.nav-group-header .chevron {
  transition: transform 200ms;
}

.nav-section.open .chevron,
.nav-group.open .chevron {
  transform: rotate(90deg);
}
.nav-section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  cursor: pointer;
  font-size: 12px;
  /* 从 11px 略微增大 */
  font-weight: 700;
  /* 从 600 加重，视觉更实 */
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--text-2);
  /* 从 text-3 提升到 text-2，更显眼 */
  user-select: none;
  transition: all 150ms;
  border-bottom: 1px solid transparent;
}

.nav-section-header:hover {
  color: var(--text);
  background: rgba(0, 0, 0, 0.02);
}

.nav-section-header .chevron {
  transition: transform 200ms;
  font-size: 10px;
  opacity: 0.6;
  transform: rotate(0deg);
}

.nav-section.open .chevron {
  transform: rotate(90deg);
}

.nav-section-items {
  display: none;
  padding: 4px 0;
}

.nav-section.open .nav-section-items {
  display: block;
}

/* 二级：著作分组（如 著作 (1-43卷)） */
.nav-group {
  margin: 0;
  border-bottom: 1px solid var(--border-light);
}

.nav-group:last-child {
  border-bottom: none;
}

.nav-group-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 16px 8px 24px;
  /* 增加左缩进，强化层级感 */
  cursor: pointer;
  font-size: 13px;
  /* 从 14px 降到 13px */
  color: var(--text-2);
  transition: all 150ms;
  font-weight: 400;
  /* 从 500 降到 400，不抢眼 */
  background: transparent;
}

.nav-group-header:hover {
  color: var(--text);
  background: rgba(0, 0, 0, 0.03);
}

.nav-group-header .chevron {
  font-size: 10px;
  transition: transform 200ms;
  opacity: 0.5;
}

.nav-group.open .chevron {
  transform: rotate(90deg);
}

.nav-group-items {
  display: none;
  padding-bottom: 4px;
}

.nav-group.open .nav-group-items {
  display: block;
}

/* 三级：卷号列表（如 第1卷 (1893年...)） */
.nav-item {
  display: block;
  padding: 7px 16px 7px 32px;
  font-size: 13px;
  color: var(--text-2);
  text-decoration: none;
  border-left: 2px solid transparent;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: all 120ms;
  line-height: 1.5;
}

.nav-item:hover {
  color: var(--text);
  background: rgba(0, 0, 0, 0.04);
  border-left-color: var(--accent);
  padding-left: 34px;
}

.nav-item.active {
  color: var(--accent);
  background: var(--bg-active);
  border-left-color: var(--accent);
  font-weight: 500;
}

/* ═══════════════════════════════════════════════
   主内容区
═══════════════════════════════════════════════ */
#main {
  flex: 1;
  min-height: 100vh;
  padding-top: calc(var(--nav-h) + 40px);
  padding-bottom: 80px;
  margin-left: 0;
  width: 100%;
}

/* 欢迎页 */
/* ═══════════════════════════════════════════════
   欢迎页与卡片网格
═══════════════════════════════════════════════ */
#welcome {
  max-width: 640px;
  margin: 0 auto;
  padding: 60px 20px;
  text-align: center;
  display: block;
  /* 确保默认显示 */
}

#welcome h1 {
  font-family: var(--font-serif);
  font-size: 2.2em;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  color: var(--text);
}

#welcome p {
  font-size: 15px;
  color: var(--text-2);
  line-height: 1.7;
  margin-bottom: 40px;
}

/* 卡片网格容器 */
.library-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
  text-align: left;
  margin-top: 24px;
}

/* 单个卡片 */
.library-card {
  padding: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all 150ms ease;
  text-decoration: none;
  display: block;
}

.library-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.library-card .card-tag {
  font-size: 11px;
  font-family: var(--font-mono);
  color: var(--text-3);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.library-card .card-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
  line-height: 1.4;
}

.library-card .card-desc {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.5;
}

/* 加载中 */
#loading {
  display: none;
  padding: 80px 0;
  text-align: center;
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 16px;
}

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

.loading-text {
  font-size: 13px;
  color: var(--text-3);
}

/* 文档视图 */
#doc-view {
  width: min(720px, 90%);
  margin: 0 auto;
}

#doc-header {
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

#doc-pathbar {
  font-size: 13px;
  color: var(--text-3);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  line-height: 1.6;
}

#doc-collection {
  font-weight: 600;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

#doc-filename {
  color: var(--text-2);
  font-family: var(--font-mono);
  font-size: 12px;
}

#doc-title-display {
  color: var(--text-2);
  font-style: italic;
  font-size: 13px;
  max-width: 300px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.sep {
  color: var(--text-3);
  opacity: 0.4;
  font-size: 11px;
}

/* ═══════════════════════════════════════════════
   内容排版 —— 修复标题颜色 & 锚点样式 & 链接样式
═══════════════════════════════════════════════ */
#content {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text);
}

/* 修复：所有标题统一使用 var(--text)，解决变浅问题 */
#content h1,
#content h2,
#content h3,
#content h4,
#content h5,
#content h6 {
  font-family: var(--font-sans);
  font-weight: 600;
  line-height: 1.3;
  color: var(--text);
  /* 强制主色，防止变浅 */
  scroll-margin-top: 80px;
}

/* h1 采用第二份的下边框样式（1px 柔和边框） */
#content h1 {
  font-size: 1.75em;
  margin: 0 0 0.6em;
  padding-bottom: 0.4em;
  border-bottom: 1px solid var(--border);
}

#content h2 {
  font-size: 1.35em;
  margin: 1.8em 0 0.6em;
}

#content h3 {
  font-size: 1.15em;
  margin: 1.5em 0 0.5em;
}

#content h4 {
  font-size: 1em;
  margin: 1.3em 0 0.3em;
}

#content h5 {
  font-size: 0.95em;
  margin: 1.2em 0 0.3em;
  color: var(--text);
  /* 确保 h5 不是灰色 */
}

/* 锚点样式 —— 第二份风格（默认隐藏，hover 显示，柔和颜色） */
#content h2 .anchor,
#content h3 .anchor,
#content h4 .anchor,
#content h5 .anchor {
  opacity: 0;
  margin-left: 6px;
  color: var(--text-3);
  /* 柔和灰色 */
  text-decoration: none;
  font-size: 0.8em;
  font-weight: 400;
  transition: opacity 150ms ease;
}

#content h2:hover .anchor,
#content h3:hover .anchor,
#content h4:hover .anchor,
#content h5:hover .anchor {
  opacity: 1;
}

#content p {
  margin: 0 0 1.2em;
  text-align: justify;
  hyphens: auto;
  /* 默认：英文段首缩进2字符 */
}
#content strong,
#content b {
  color: var(--text);
  /* 强制主色，不要变浅 */
  font-weight: 700;
  /* 确保加粗程度 */
  font-family: var(--font-sans);
  /* 中文粗体用黑体更清晰 */
}
[data-theme="dark"] #content strong,
[data-theme="dark"] #content b {
  color: var(--text);
  /* 深色模式也保持白色/主色，不变成灰色 */
}
/* 中文内容：取消缩进，改用段间距，关闭连字符 */
/* 链接样式 —— 第二份风格（带下划线偏移） */
#content a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--link) 30%, transparent);
  text-underline-offset: 2px;
  transition: color 150ms ease;
}

#content a:hover {
  color: var(--link-hover);
  text-decoration-color: var(--link-hover);
}

/* 脚注链接特殊样式 */
#content a.fn-ref,
#content sup a,
#content a[href^="#fn"],
#content a[href^="#FN"] {
  font-size: 0.72em;
  vertical-align: super;
  line-height: 0;
  color: var(--accent);
  text-decoration: none;
  font-family: var(--font-mono);
  font-weight: 400;
  padding: 0 1px;
}

#content a.fn-ref:hover {
  color: var(--accent-2);
}

#content blockquote {
  margin: 1.6em 0;
  padding: 14px 20px;
  border-left: 3px solid var(--accent);
  background: var(--accent-bg);
  border-radius: 0 8px 8px 0;
  font-style: italic;
  color: var(--text-2);
}

#content blockquote p:last-child {
  margin-bottom: 0;
}

#content pre,
#content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

#content code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent-2);
}

#content pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  overflow-x: auto;
  margin: 1.4em 0;
  line-height: 1.5;
}

#content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

#content ul,
#content ol {
  margin: 0 0 1.2em 1.5em;
  padding-left: 0.5em;
}

#content li {
  margin-bottom: 0.4em;
}

#content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.4em 0;
  font-size: 0.9em;
  font-family: var(--font-sans);
}

#content th,
#content td {
  padding: 8px 12px;
  border: 1px solid var(--border);
  text-align: left;
}

#content th {
  background: var(--bg-hover);
  font-weight: 600;
  font-size: 0.85em;
  color: var(--text-2);
}

/* ═══════════════════════════════════════════════
   文档底部导航 —— 第二份 Grid 布局版本
═══════════════════════════════════════════════ */
#doc-footer {
  margin-top: 64px;
  padding-top: 28px;
  border-top: 1px solid var(--border);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  font-family: var(--font-sans);
  width: 100%;
  min-width: 0;
}

.doc-nav-btn {
  display: flex;
  flex-direction: column;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: 6px;
  text-decoration: none;
  color: var(--text);
  background: var(--bg-card);
  transition: all 150ms ease;
  cursor: pointer;
  min-width: 0;
  overflow: hidden;
}

.doc-nav-btn:hover {
  border-color: var(--accent);
  background: var(--accent-bg);
}

.doc-nav-btn.next {
  align-items: flex-end;
  text-align: right;
}

.doc-nav-btn.prev {
  align-items: flex-start;
}

.doc-nav-btn .dir {
  font-size: 11px;
  color: var(--text-3);
  margin-bottom: 4px;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  flex-shrink: 0;
}

.doc-nav-btn .doc-name {
  font-size: 13.5px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
  min-width: 0;
  width: 100%;
}

/* 导航箭头样式（可选增强） */
.doc-nav-btn .nav-arrow {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--accent);
  flex-shrink: 0;
  margin-right: 6px;
}

.doc-nav-btn.next .nav-arrow {
  margin-right: 0;
  margin-left: 6px;
}

/* ═══════════════════════════════════════════════
   右侧目录（TOC）—— 同样采用细滚动条
═══════════════════════════════════════════════ */
#rsidebar {
  display: none;
  position: fixed;
  right: 0;
  top: var(--nav-h);
  width: var(--sidebar-r);
  height: calc(100vh - var(--nav-h));
  padding: 24px 20px;
  overflow-y: auto;
  overflow-x: hidden;
  border-left: 1px solid var(--border);
  background: var(--bg);
  z-index: 100;

  /* 细滚动条 */
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

#rsidebar::-webkit-scrollbar {
  width: 3px;
}

#rsidebar::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

@media(min-width:1280px) {
  #rsidebar {
    display: block;
  }

  #main {
    padding-right: calc(var(--sidebar-r) / 2);
  }
}

#toc-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-light);
}

.toc-item {
  display: block;
  padding: 5px 10px;
  font-size: 13px;
  color: var(--text-3);
  text-decoration: none;
  border-radius: 4px;
  margin-bottom: 2px;
  transition: all 120ms;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  border-left: 2px solid transparent;
}

.toc-item:hover {
  color: var(--text);
  background: var(--bg-hover);
  border-left-color: var(--border);
}

.toc-item.active {
  color: var(--accent);
  background: var(--bg-active);
  border-left-color: var(--accent);
  font-weight: 500;
}

.toc-item.toc-h3 {
  padding-left: 20px;
  font-size: 12px;
}

/* 搜索浮层 */
#search-overlay {
  display: none;
  position: fixed;
  top: calc(var(--nav-h) + 8px);
  left: 50%;
  transform: translateX(-50%);
  width: min(480px, 90vw);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-md);
  z-index: 400;
  max-height: 60vh;
  overflow-y: auto;
}

#search-overlay.visible {
  display: block;
}

.search-result {
  padding: 12px 16px;
  cursor: pointer;
  border-bottom: 1px solid var(--border-light);
  transition: background 120ms;
}

.search-result:hover {
  background: var(--bg-hover);
}

.search-no-results {
  padding: 24px;
  color: var(--text-3);
  text-align: center;
  font-size: 14px;
}

/* 脚注提示 */
#fn-tooltip {
  position: fixed;
  z-index: 500;
  max-width: 320px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  font-size: 13px;
  line-height: 1.5;
  box-shadow: var(--shadow-md);
  pointer-events: none;
  opacity: 0;
  transition: opacity 150ms;
}

#fn-tooltip.visible {
  opacity: 1;
}

/* ═══════════════════════════════════════════════
   响应式
═══════════════════════════════════════════════ */
@media(max-width:768px) {
  :root {
    --sidebar-w: 85vw;
  }

  .desktop-tools {
    display: none !important;
  }

  .mobile-menu-btn {
    display: flex;
  }

  #search-bar {
    width: 36px;
    padding: 0;
    justify-content: center;
    background: transparent;
    border: none;
  }

  #search-bar.expanded {
    position: absolute;
    right: 50px;
    top: 10px;
    width: calc(100vw - 100px);
    max-width: 300px;
    padding: 0 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    z-index: 301;
  }

  #search-bar input {
    display: none;
  }

  #search-bar.expanded input {
    display: block;
  }

  #lsidebar {
    max-width: 360px;
    box-shadow: 4px 0 30px rgba(0, 0, 0, 0.2);
  }

  #rsidebar {
    display: none !important;
  }

  #main {
    padding-right: 0;
  }

  #doc-view {
    width: calc(100vw - 32px);
    padding: 0 16px;
  }

  /* 移动端页尾导航改为单列 */
  #doc-footer {
    grid-template-columns: 1fr;
    gap: 12px;
    margin-top: 48px;
    padding-top: 24px;
  }

  .doc-nav-btn.next {
    align-items: flex-start;
    text-align: left;
  }

  /* 移动端改为横向排列 */
  .doc-nav-btn {
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    gap: 8px;
    padding: 12px 16px;
    text-align: left;
  }

  .doc-nav-btn.next {
    flex-direction: row-reverse;
    justify-content: flex-end;
    text-align: right;
  }

  .doc-nav-btn .dir {
    margin-bottom: 0;
    font-size: 12px;
  }

  .doc-nav-btn .doc-name {
    flex: 1;
    font-size: 13px;
  }

  .doc-nav-btn.next .doc-name {
    text-align: right;
  }
}

@media(min-width:769px) {
  #sidebar-toggle {
    display: flex !important;
  }

  .mobile-menu-btn {
    display: none !important;
  }

  #mobile-menu {
    display: none !important;
  }
}

/* 打印 */
@media print {

  #navbar,
  #lsidebar,
  #rsidebar,
  #sidebar-backdrop,
  #progress-bar,
  #mobile-menu {
    display: none !important;
  }

  #main {
    padding-top: 20px;
  }

  #doc-view {
    width: 100%;
    max-width: none;
  }
}