:root {
  --ink: #181612;
  --muted: #706a5f;
  --paper: #f6f0e6;
  --paper-deep: #e8dccb;
  --panel: rgba(255, 252, 246, 0.78);
  --line: rgba(24, 22, 18, 0.16);
  --accent: #b6402b;
  --accent-dark: #7e2417;
  --olive: #556b43;
  --code: #241f1a;
  --code-text: #f5ead8;
  --shadow: 0 24px 80px rgba(39, 30, 18, 0.18);
  --page-gap: 20px;
  /* dvh 避免移动端/桌面浏览器 chrome 导致 100vh 偏高把底部裁切 */
  --panel-height: calc(100dvh - (var(--page-gap) * 2));
  --scroll-size: 8px;
  --scroll-track: transparent;
  --scroll-thumb: rgba(24, 22, 18, 0.22);
  --scroll-thumb-hover: rgba(126, 36, 23, 0.55);
  --scroll-thumb-active: rgba(182, 64, 43, 0.72);
  --scroll-code-thumb: rgba(245, 234, 216, 0.28);
  --scroll-code-thumb-hover: rgba(245, 234, 216, 0.48);

  /*
   * 字号阶梯（相对旧版整体放大约 15–25%）
   * 阅读正文优先清晰；标签/元信息不低于 12px，避免 10–11px 难辨认。
   */
  --fs-2xs: 12px; /* 原 ~10px：极小角标 */
  --fs-xs: 13px; /* 原 ~11px：标签、状态 */
  --fs-sm: 14px; /* 原 ~12px：辅助信息 */
  --fs-md: 15px; /* 原 ~13px：次要列表/大纲 */
  --fs-base: 16px; /* 原 ~14px：UI 正文、聊天气泡 */
  --fs-doc: 17px; /* 原 ~15px：侧栏文档标题 */
  --fs-cat: 18px; /* 侧栏分类类型标题（编程语言 / AI 等） */
  --fs-lg: 18px; /* 强调/欢迎导语 */
  --fs-xl: 24px; /* 面板小标题 */
  --fs-2xl: 30px; /* 侧栏品牌标题 */
  --fs-3xl: 36px;
  --fs-reader-title: clamp(36px, 4.2vw, 56px);
  --fs-body: clamp(18px, 1.05vw + 13px, 21px); /* 正文，原 16–18 */
  --fs-h1: clamp(36px, 2.5vw + 22px, 50px);
  --fs-h2: clamp(28px, 1.6vw + 18px, 38px);
  --fs-h3: clamp(22px, 1vw + 15px, 28px);
  --lh-tight: 1.25;
  --lh-ui: 1.45;
  --lh-body: 1.88;
}

/* 统一细滚动条：暖纸底 + 墨色滑块，hover 偏 accent */
* {
  box-sizing: border-box;
  scrollbar-width: thin;
  scrollbar-color: var(--scroll-thumb) var(--scroll-track);
}

*::-webkit-scrollbar {
  width: var(--scroll-size);
  height: var(--scroll-size);
}

*::-webkit-scrollbar-track {
  background: var(--scroll-track);
  border-radius: 999px;
}

*::-webkit-scrollbar-thumb {
  background: var(--scroll-thumb);
  border: 2px solid transparent;
  border-radius: 999px;
  background-clip: content-box;
}

*::-webkit-scrollbar-thumb:hover {
  background: var(--scroll-thumb-hover);
  border: 2px solid transparent;
  background-clip: content-box;
}

*::-webkit-scrollbar-thumb:active {
  background: var(--scroll-thumb-active);
  border: 2px solid transparent;
  background-clip: content-box;
}

*::-webkit-scrollbar-corner {
  background: transparent;
}

html {
  height: 100%;
  background:
    radial-gradient(circle at 18% 12%, rgba(182, 64, 43, 0.18), transparent 28rem),
    radial-gradient(circle at 92% 8%, rgba(85, 107, 67, 0.16), transparent 24rem),
    linear-gradient(135deg, #f8f1e7 0%, #e7d8c4 100%);
}

body {
  height: 100%;
  min-height: 100vh;
  margin: 0;
  overflow: hidden;
  color: var(--ink);
  font-family: Georgia, "Times New Roman", "Noto Serif SC", "Songti SC", serif;
  font-size: var(--fs-base);
  line-height: var(--lh-ui);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  content: "";
  opacity: 0.36;
  background-image:
    linear-gradient(rgba(24, 22, 18, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(24, 22, 18, 0.035) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: linear-gradient(to bottom, #000, transparent 78%);
}

button,
input {
  font: inherit;
}

.shell {
  display: grid;
  /* 侧栏弹性宽度，中间阅读区吃掉剩余空间 */
  grid-template-columns:
    clamp(220px, 18vw, 320px)
    minmax(0, 1fr)
    clamp(280px, 22vw, 420px);
  grid-template-rows: minmax(0, 1fr);
  align-items: stretch;
  gap: clamp(12px, 1.2vw, 20px);
  /* 贴合窗口宽度，仅保留页边留白 */
  width: calc(100vw - (var(--page-gap) * 2));
  max-width: none;
  height: var(--panel-height);
  max-height: var(--panel-height);
  margin: var(--page-gap) auto;
  overflow: hidden;
}

.library-panel,
.reader,
.ai-panel {
  height: 100%;
  max-height: 100%;
  min-height: 0;
  min-width: 0;
  border: 1px solid var(--line);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
  overflow: hidden;
}

.library-panel {
  display: flex;
  flex-direction: column;
  padding: 24px;
}

.brand {
  display: grid;
  grid-template-columns: 58px 1fr;
  gap: 16px;
  align-items: center;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.brand-mark {
  display: block;
  width: 58px;
  height: 58px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 3px 3px 0 rgba(24, 22, 18, 0.18);
  transform: rotate(-4deg);
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2 {
  margin: 0;
  line-height: 1.1;
  letter-spacing: 0;
}

h1 {
  font-size: var(--fs-2xl);
}

.search-box {
  display: grid;
  gap: 8px;
  margin: 24px 0 14px;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
  font-weight: 700;
  text-transform: uppercase;
}

.search-box input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 0;
  padding: 13px 14px;
  outline: none;
  background: rgba(255, 249, 238, 0.72);
  color: var(--ink);
}

.search-box input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(182, 64, 43, 0.12);
}

.meta-row {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 10px;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
}

.menu-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.menu-tool-btn {
  flex: 1 1 auto;
  min-width: 0;
  border: 1px solid var(--line);
  padding: 8px 12px;
  background: rgba(255, 249, 238, 0.72);
  color: var(--ink);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease, color 160ms ease;
}

.menu-tool-btn:hover {
  border-color: rgba(182, 64, 43, 0.45);
  background: #fff8ed;
  color: var(--accent-dark);
}

.menu-tool-btn:focus-visible {
  outline: 2px solid rgba(182, 64, 43, 0.45);
  outline-offset: 2px;
}

.doc-list {
  overflow: auto;
  display: grid;
  gap: 10px;
  min-height: 0;
  /* 给细滚动条留一点槽位，避免列表文字贴滑块 */
  padding-right: 6px;
  /* 与面板底部 padding 叠加，滚动时列表末项仍不贴边 */
  padding-bottom: 4px;
  scrollbar-gutter: stable;
}

.doc-empty {
  display: grid;
  place-items: center;
  min-height: 120px;
  border: 1px dashed var(--line);
  padding: 18px 12px;
  color: var(--muted);
  font-size: var(--fs-md);
  text-align: center;
}

.doc-empty p {
  margin: 0;
}

/* 分类分组：可折叠的行业菜单 */
.doc-category {
  border: 1px solid transparent;
  background: transparent;
}

.doc-category.has-active {
  border-color: rgba(182, 64, 43, 0.18);
  background: rgba(255, 249, 238, 0.35);
}

.doc-category-toggle {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr) auto;
  gap: 8px;
  align-items: center;
  width: 100%;
  border: 1px solid transparent;
  padding: 12px 10px;
  background: rgba(255, 249, 238, 0.42);
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease;
}

.doc-category-toggle:hover {
  border-color: var(--line);
  background: rgba(255, 249, 238, 0.9);
}

.doc-category-toggle:focus-visible {
  outline: 2px solid rgba(182, 64, 43, 0.4);
  outline-offset: 2px;
}

.doc-category.is-open > .doc-category-toggle {
  border-color: rgba(24, 22, 18, 0.1);
  background: rgba(255, 249, 238, 0.82);
}

.doc-category-chevron {
  width: 0;
  height: 0;
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
  border-left: 6px solid var(--muted);
  justify-self: center;
  transition: transform 160ms ease;
}

.doc-category.is-open .doc-category-chevron {
  transform: rotate(90deg);
  border-left-color: var(--accent-dark);
}

.doc-category-label {
  min-width: 0;
  overflow: hidden;
  font-size: var(--fs-cat);
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.doc-category-count {
  min-width: 1.7em;
  border: 1px solid rgba(24, 22, 18, 0.1);
  padding: 3px 8px;
  background: rgba(255, 252, 246, 0.9);
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  text-align: center;
}

.doc-category.has-active .doc-category-count {
  border-color: rgba(182, 64, 43, 0.28);
  color: var(--accent-dark);
}

.doc-category-body {
  display: grid;
  gap: 4px;
  margin-top: 4px;
  padding: 0 0 2px 8px;
  border-left: 2px solid rgba(24, 22, 18, 0.08);
}

.doc-category-body[hidden] {
  display: none !important;
}

.doc-item {
  width: 100%;
  border: 1px solid transparent;
  padding: 11px 10px;
  background: transparent;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease;
}

.doc-item:hover {
  border-color: var(--line);
  background: rgba(255, 249, 238, 0.74);
  transform: translateX(4px);
}

.doc-item.active {
  border-color: rgba(182, 64, 43, 0.5);
  background: #fff8ed;
  box-shadow: inset 4px 0 0 var(--accent);
}

.doc-title {
  display: block;
  overflow-wrap: anywhere;
  font-size: var(--fs-doc);
  font-weight: 700;
  line-height: 1.4;
}

.doc-file {
  display: block;
  margin-top: 5px;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-2xs);
  line-height: 1.4;
  word-break: break-all;
}

@media (prefers-reduced-motion: reduce) {
  .doc-category-chevron,
  .doc-item {
    transition: none;
  }
}

.reader {
  position: relative;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* 真正滚动的是这一层；进度浮层挂在 .reader 上，不跟着正文滚走 */
.reader-scroll {
  flex: 1 1 auto;
  min-height: 0;
  min-width: 0;
  overflow: auto;
  /* 底部多留空，避免末段正文被右下角进度浮层挡住 */
  padding: 34px clamp(24px, 5vw, 72px) 96px;
  scrollbar-gutter: stable;
}

.reader-topline {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  flex: 0 0 auto;
  margin-bottom: 22px;
}

.reader-heading {
  min-width: 0;
}

.reader-topline h2 {
  max-width: min(1100px, 100%);
  font-size: var(--fs-reader-title);
}

/*
 * 阅读进度：文档页右下角悬浮卡片。
 * 不占标题区、不挡首屏；需要时才扫一眼，可点可拖跳转。
 */
.reader-status {
  position: absolute;
  right: max(16px, env(safe-area-inset-right, 0px));
  bottom: max(16px, env(safe-area-inset-bottom, 0px));
  z-index: 8;
  width: min(300px, calc(100% - 32px));
  margin: 0;
  padding: 12px 14px 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 252, 246, 0.94);
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.55) inset,
    0 14px 40px rgba(39, 30, 18, 0.14);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  pointer-events: auto;
}

.reader-status[hidden] {
  display: none !important;
}

.reader-status__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}

.reader-status__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  min-width: 0;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.reader-status__sep {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: rgba(24, 22, 18, 0.28);
}

.reader-status__right {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

.reader-status__percent {
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.04em;
  min-width: 3.2em;
  text-align: right;
}

.reader-status__top {
  border: 1px solid var(--line);
  padding: 5px 10px;
  background: rgba(255, 249, 238, 0.9);
  color: var(--ink);
  font-family: "Courier New", monospace;
  font-size: var(--fs-2xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
  transition: border-color 140ms ease, background 140ms ease, opacity 160ms ease;
}

.reader-status__top:hover {
  border-color: rgba(182, 64, 43, 0.45);
  background: #fff8ed;
}

.reader-status__top[hidden] {
  display: none !important;
}

/* 可点击进度轨：加高命中区，视觉仍保持细线 */
.reader-status__track {
  position: relative;
  height: 10px;
  margin: 0;
  padding: 3px 0;
  cursor: pointer;
  touch-action: none;
  outline: none;
  user-select: none;
}

.reader-status__track::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 3px;
  transform: translateY(-50%);
  border-radius: 999px;
  background: rgba(24, 22, 18, 0.1);
}

.reader-status__fill {
  position: absolute;
  left: 0;
  top: 50%;
  height: 3px;
  width: 100%;
  transform: translateY(-50%) scaleX(0);
  transform-origin: left center;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent-dark), var(--accent));
  box-shadow: 0 0 10px rgba(182, 64, 43, 0.28);
  will-change: transform;
  pointer-events: none;
}

.reader-status__thumb {
  position: absolute;
  top: 50%;
  left: 0;
  width: 11px;
  height: 11px;
  margin-left: -5.5px;
  border: 2px solid #fff9ef;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 1px 4px rgba(39, 30, 18, 0.22);
  transform: translateY(-50%);
  pointer-events: none;
  opacity: 0;
  transition: opacity 140ms ease, box-shadow 140ms ease;
}

.reader-status__track:hover .reader-status__thumb,
.reader-status__track:focus-visible .reader-status__thumb,
.reader-status.is-seeking .reader-status__thumb,
.reader-status.has-progress .reader-status__thumb {
  opacity: 1;
}

.reader-status__track:focus-visible {
  box-shadow: 0 0 0 3px rgba(182, 64, 43, 0.16);
  border-radius: 4px;
}

.reader-status.is-seeking .reader-status__thumb {
  box-shadow: 0 0 0 4px rgba(182, 64, 43, 0.16), 0 1px 4px rgba(39, 30, 18, 0.22);
}

.reader-status.is-complete .reader-status__fill {
  animation: progress-breathe 2.6s ease-in-out infinite;
}

.reader-status.is-complete .reader-status__percent {
  color: var(--olive);
}

@keyframes progress-breathe {
  0%,
  100% {
    filter: brightness(1);
  }
  50% {
    filter: brightness(1.1);
  }
}

@media (prefers-reduced-motion: reduce) {
  .reader-status.is-complete .reader-status__fill {
    animation: none;
  }

  .reader-status__top,
  .reader-status__thumb,
  .markdown-body .code-copy-btn {
    transition: none;
  }

  .markdown-body .code-copy-btn.is-copied .code-copy-icon--done {
    animation: none;
  }
}

.raw-link {
  flex: 0 0 auto;
  border: 1px solid var(--ink);
  padding: 10px 14px;
  background: var(--ink);
  color: #fff9ef;
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
  font-weight: 700;
  text-decoration: none;
  text-transform: uppercase;
}

.raw-link[hidden] {
  display: none !important;
}

.reader-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(180px, 220px);
  gap: clamp(20px, 3vw, 40px);
  align-items: start;
  /* 额外底部空隙：滚到文档末尾时正文/大纲仍与面板底边保持距离 */
  padding-bottom: 28px;
}

.markdown-body {
  /* 宽屏可更舒展，但仍限制行长避免过宽难读 */
  max-width: min(1100px, 100%);
  min-width: 0;
  width: 100%;
  font-size: var(--fs-body);
  line-height: var(--lh-body);
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  margin: 2.1em 0 0.65em;
  line-height: var(--lh-tight);
  /* 大纲跳转时略留顶边空隙（进度条已改右下角，不再预留吸顶高度） */
  scroll-margin-top: 20px;
}

.markdown-body h1 {
  font-size: var(--fs-h1);
}

.markdown-body h2 {
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: var(--fs-h2);
}

.markdown-body h3 {
  color: var(--accent-dark);
  font-size: var(--fs-h3);
}

.markdown-body h4 {
  font-size: 1.15em;
}

.markdown-body p {
  margin: 0 0 1.1em;
}

.markdown-body a {
  color: var(--accent-dark);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 1.35em;
}

.markdown-body li {
  margin: 0.35em 0;
}

.markdown-body blockquote {
  margin: 1.5em 0;
  border-left: 4px solid var(--accent);
  padding: 0.7em 1.2em;
  background: rgba(255, 249, 238, 0.62);
  color: #453d33;
}

.markdown-body code {
  border: 1px solid rgba(24, 22, 18, 0.12);
  padding: 0.1em 0.34em;
  background: rgba(255, 249, 238, 0.8);
  font-family: "Cascadia Code", "Courier New", monospace;
  font-size: 0.9em;
}

/* 围栏代码块：容器承载语言标签 + 悬停复制按钮 */
.markdown-body .code-block {
  position: relative;
  margin: 1.5em 0;
  border: 1px solid rgba(255, 249, 238, 0.16);
  background: var(--code);
  color: var(--code-text);
  box-shadow: 0 18px 48px rgba(36, 31, 26, 0.24);
}

.markdown-body .code-block-lang {
  position: absolute;
  top: 8px;
  left: 12px;
  z-index: 1;
  pointer-events: none;
  color: rgba(245, 234, 216, 0.55);
  font-family: "Cascadia Code", "Courier New", monospace;
  font-size: var(--fs-xs);
  letter-spacing: 0.04em;
  text-transform: lowercase;
  user-select: none;
}

.markdown-body .code-copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  margin: 0;
  border: 1px solid rgba(245, 234, 216, 0.14);
  border-radius: 7px;
  padding: 0;
  /* 深色代码底上的半透明玻璃片，避免抢内容 */
  background: rgba(18, 15, 12, 0.55);
  color: rgba(245, 234, 216, 0.72);
  box-shadow:
    0 1px 0 rgba(255, 252, 246, 0.06) inset,
    0 6px 16px rgba(0, 0, 0, 0.22);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(-2px);
  transition:
    opacity 0.18s ease,
    color 0.18s ease,
    background 0.18s ease,
    border-color 0.18s ease,
    box-shadow 0.18s ease,
    transform 0.18s ease;
}

.markdown-body .code-block:hover .code-copy-btn,
.markdown-body .code-block:focus-within .code-copy-btn,
.markdown-body .code-copy-btn:focus-visible,
.markdown-body .code-copy-btn.is-copied {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

/* 触控设备没有 hover：复制按钮常显，避免点不到 */
@media (hover: none) {
  .markdown-body .code-copy-btn {
    opacity: 1;
    pointer-events: auto;
    transform: none;
  }
}

.markdown-body .code-copy-btn:hover {
  color: rgba(255, 248, 236, 0.96);
  background: rgba(36, 28, 22, 0.78);
  border-color: rgba(245, 234, 216, 0.32);
  box-shadow:
    0 1px 0 rgba(255, 252, 246, 0.1) inset,
    0 8px 18px rgba(0, 0, 0, 0.28);
}

.markdown-body .code-copy-btn:active {
  transform: translateY(0) scale(0.94);
}

.markdown-body .code-copy-btn:focus-visible {
  outline: 2px solid rgba(182, 64, 43, 0.7);
  outline-offset: 2px;
}

.markdown-body .code-copy-btn.is-copied {
  color: #e8f0df;
  background: rgba(72, 96, 58, 0.72);
  border-color: rgba(180, 210, 150, 0.35);
  box-shadow:
    0 1px 0 rgba(255, 252, 246, 0.08) inset,
    0 6px 14px rgba(36, 50, 28, 0.28);
}

.markdown-body .code-copy-icon {
  display: block;
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
  pointer-events: none;
  overflow: visible;
}

/* 默认只显示复制图标；成功后才切换为对勾 */
.markdown-body .code-copy-icon--done,
.markdown-body .code-copy-icon[hidden] {
  display: none !important;
}

.markdown-body .code-copy-btn.is-copied .code-copy-icon--idle {
  display: none !important;
}

.markdown-body .code-copy-btn.is-copied .code-copy-icon--done {
  display: block !important;
  animation: code-copy-pop 0.28s ease;
}

@keyframes code-copy-pop {
  0% {
    opacity: 0;
    transform: scale(0.72);
  }
  60% {
    opacity: 1;
    transform: scale(1.08);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

.markdown-body .code-block pre {
  overflow: auto;
  margin: 0;
  border: 0;
  padding: 18px;
  padding-top: 40px;
  background: transparent;
  color: inherit;
  box-shadow: none;
  font-size: 0.92em;
  line-height: 1.6;
  scrollbar-color: var(--scroll-code-thumb) transparent;
}

.markdown-body pre {
  overflow: auto;
  margin: 1.5em 0;
  border: 1px solid rgba(255, 249, 238, 0.16);
  padding: 18px;
  background: var(--code);
  color: var(--code-text);
  box-shadow: 0 18px 48px rgba(36, 31, 26, 0.24);
  scrollbar-color: var(--scroll-code-thumb) transparent;
}

.markdown-body pre::-webkit-scrollbar-thumb,
.markdown-body .code-block pre::-webkit-scrollbar-thumb {
  background: var(--scroll-code-thumb);
  border: 2px solid transparent;
  background-clip: content-box;
}

.markdown-body pre::-webkit-scrollbar-thumb:hover,
.markdown-body .code-block pre::-webkit-scrollbar-thumb:hover {
  background: var(--scroll-code-thumb-hover);
  border: 2px solid transparent;
  background-clip: content-box;
}

.markdown-body pre code {
  border: 0;
  padding: 0;
  background: transparent;
  color: inherit;
}

.markdown-body .table-wrap {
  display: block;
  width: 100%;
  max-width: 100%;
  margin: 1.5em 0;
  overflow-x: auto;
  border: 1px solid var(--line);
  background: rgba(255, 252, 246, 0.72);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.4);
}

.markdown-body table {
  width: 100%;
  min-width: 480px;
  margin: 0;
  border-collapse: collapse;
  font-size: 0.95em;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--line);
  padding: 12px 16px;
  vertical-align: top;
  line-height: 1.6;
}

.markdown-body th {
  background: rgba(232, 220, 203, 0.55);
  color: var(--ink);
  font-weight: 700;
  white-space: nowrap;
}

.markdown-body tbody tr:nth-child(even) td {
  background: rgba(255, 249, 238, 0.45);
}

.markdown-body tbody tr:hover td {
  background: rgba(182, 64, 43, 0.06);
}

.markdown-body img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background: #fffdf8;
}

.markdown-body del {
  color: var(--muted);
  text-decoration: line-through;
}

.markdown-body ul.task-list {
  list-style: none;
  padding-left: 0.2em;
}

.markdown-body .task-list-item {
  display: flex;
  gap: 0.55em;
  align-items: flex-start;
}

.markdown-body .task-list-item input[type="checkbox"] {
  margin-top: 0.35em;
  accent-color: var(--accent);
}

.markdown-body hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 2.4em 0;
}

.toc-panel {
  position: sticky;
  top: 0;
  max-height: calc(var(--panel-height) - 160px);
  overflow: auto;
  border: 1px solid var(--line);
  padding: 16px 14px;
  background: rgba(255, 249, 238, 0.55);
  scrollbar-gutter: stable;
}

.toc-heading {
  margin: 0 0 12px;
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.toc-list {
  display: grid;
  gap: 4px;
}

.toc-item {
  display: block;
  overflow: hidden;
  border-left: 2px solid transparent;
  padding: 7px 10px;
  color: var(--muted);
  font-size: var(--fs-md);
  line-height: 1.45;
  text-decoration: none;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: color 160ms ease, border-color 160ms ease, background 160ms ease;
}

.toc-item:hover {
  border-left-color: rgba(182, 64, 43, 0.35);
  background: rgba(255, 249, 238, 0.9);
  color: var(--ink);
}

.toc-item.active {
  border-left-color: var(--accent);
  background: #fff8ed;
  color: var(--ink);
  font-weight: 700;
}

.toc-level-1 {
  padding-left: 8px;
  font-weight: 700;
  color: var(--ink);
}

.toc-level-2 {
  padding-left: 14px;
}

.toc-level-3 {
  padding-left: 22px;
  font-size: var(--fs-sm);
}

.toc-level-4 {
  padding-left: 30px;
  font-size: var(--fs-sm);
}

.toc-empty {
  margin: 0;
  color: var(--muted);
  font-size: var(--fs-md);
  line-height: 1.5;
}

.empty-state {
  display: grid;
  min-height: 360px;
  place-items: center;
  border: 1px dashed var(--line);
  color: var(--muted);
}

/* 未选文档时的欢迎 / 空白页 */
.welcome-page {
  display: grid;
  min-height: min(560px, calc(var(--panel-height) - 180px));
  place-items: center;
  padding: 8px 0 24px;
}

.welcome-card {
  width: min(640px, 100%);
  border: 1px solid var(--line);
  padding: clamp(28px, 4vw, 40px) clamp(22px, 3.5vw, 36px);
  background:
    linear-gradient(165deg, rgba(255, 252, 246, 0.96) 0%, rgba(246, 236, 220, 0.88) 100%);
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.55) inset,
    0 18px 48px rgba(39, 30, 18, 0.08);
}

.welcome-card--error {
  border-color: rgba(182, 64, 43, 0.35);
}

.welcome-kicker {
  margin: 0 0 10px;
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.welcome-title {
  margin: 0 0 12px;
  font-size: clamp(32px, 3.4vw, 44px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: 0;
}

.welcome-lead {
  margin: 0 0 22px;
  color: #4a4339;
  font-size: var(--fs-lg);
  line-height: 1.75;
}

.welcome-lead strong {
  color: var(--ink);
  font-weight: 700;
}

.welcome-hint {
  margin: 0;
  color: var(--muted);
  font-size: var(--fs-base);
  line-height: 1.6;
}

.welcome-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin: 0 0 24px;
}

.welcome-stat {
  display: grid;
  gap: 4px;
  border: 1px solid rgba(24, 22, 18, 0.1);
  padding: 12px 10px;
  background: rgba(255, 249, 238, 0.72);
  text-align: center;
}

.welcome-stat-value {
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xl);
  font-weight: 700;
  line-height: 1.1;
}

.welcome-stat-label {
  color: var(--muted);
  font-size: var(--fs-sm);
  letter-spacing: 0.02em;
}

.welcome-section {
  margin: 0 0 22px;
}

.welcome-section-title {
  margin: 0 0 10px;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.welcome-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.welcome-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--line);
  padding: 8px 12px;
  background: rgba(255, 252, 246, 0.9);
  color: var(--ink);
  cursor: pointer;
  transition: border-color 150ms ease, background 150ms ease, transform 150ms ease;
}

.welcome-chip:hover {
  border-color: rgba(182, 64, 43, 0.4);
  background: #fff8ed;
  transform: translateY(-1px);
}

.welcome-chip:focus-visible {
  outline: 2px solid rgba(182, 64, 43, 0.45);
  outline-offset: 2px;
}

.welcome-chip-label {
  font-size: var(--fs-cat);
  font-weight: 700;
}

.welcome-chip-count {
  min-width: 1.4em;
  border: 1px solid rgba(24, 22, 18, 0.1);
  padding: 0 6px;
  background: rgba(255, 249, 238, 0.95);
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  text-align: center;
}

.welcome-tips {
  margin: 0;
  padding: 14px 0 0 1.15em;
  border-top: 1px solid var(--line);
  color: #524b41;
  font-size: var(--fs-base);
  line-height: 1.7;
}

.welcome-tips li {
  margin: 0.35em 0;
}

.welcome-tips li::marker {
  color: var(--accent);
}

@media (max-width: 640px) {
  .welcome-stats {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  .welcome-chip {
    transition: none;
  }
}

/* —— 右侧 AI 助手 —— */
.ai-panel {
  display: flex;
  flex-direction: column;
  /* 固定占满 shell 行高，内部再分消息区 / 输入区 */
  padding: 16px 14px 12px;
}

.ai-header {
  flex: 0 0 auto;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.ai-title {
  margin: 0;
  font-size: var(--fs-xl);
  line-height: 1.15;
}

.ai-header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

.ai-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  max-width: 130px;
  overflow: hidden;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  text-overflow: ellipsis;
  text-transform: uppercase;
  white-space: nowrap;
}

.ai-status::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--muted);
  flex: 0 0 auto;
}

.ai-status.is-ok::before {
  background: var(--olive);
}

.ai-status.is-busy::before {
  background: var(--accent);
  box-shadow: 0 0 0 3px rgba(182, 64, 43, 0.18);
}

.ai-status.is-error::before {
  background: #a33;
}

.ai-icon-btn {
  border: 1px solid var(--line);
  padding: 8px 12px;
  background: rgba(255, 249, 238, 0.72);
  color: var(--ink);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  text-transform: uppercase;
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease;
}

.ai-icon-btn:hover {
  border-color: rgba(182, 64, 43, 0.45);
  background: #fff8ed;
}

.ai-context-hint {
  flex: 0 0 auto;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: var(--fs-sm);
  line-height: 1.5;
}

.ai-config-notice {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin: 10px 0 0;
  border: 1px dashed rgba(182, 64, 43, 0.42);
  padding: 9px 11px;
  background: rgba(255, 248, 237, 0.82);
  color: var(--accent-dark);
  font-size: var(--fs-sm);
  line-height: 1.45;
}

.ai-config-notice[hidden] {
  display: none !important;
}

.ai-inline-action {
  flex: 0 0 auto;
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--accent-dark);
  font-weight: 700;
  text-decoration: underline;
  cursor: pointer;
}

.ai-config-dialog {
  width: min(460px, calc(100vw - 32px));
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--ink);
}

.ai-config-dialog::backdrop {
  background: rgba(24, 22, 18, 0.45);
  backdrop-filter: blur(3px);
}

.ai-config-card {
  display: grid;
  gap: 16px;
  border: 1px solid var(--line);
  padding: 22px;
  background: #fffaf1;
  box-shadow: 0 24px 70px rgba(39, 30, 18, 0.24);
}

.ai-config-heading,
.ai-config-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.ai-config-heading h2 { margin: 0; font-size: 1.45rem; }
.ai-config-description { margin: 0; color: var(--muted); font-size: var(--fs-sm); line-height: 1.6; }
.ai-config-field { display: grid; gap: 7px; color: var(--muted); font-size: var(--fs-sm); font-weight: 700; }
.ai-config-field input { width: 100%; box-sizing: border-box; border: 1px solid var(--line); padding: 11px 12px; background: #fffdf8; color: var(--ink); font: inherit; font-weight: 400; }
.ai-config-field input:focus { outline: 2px solid rgba(182, 64, 43, 0.25); border-color: var(--accent); }

.ai-body {
  position: relative;
  flex: 1 1 0;
  min-height: 0;
  display: flex;
  flex-direction: column;
  margin: 10px 0 8px;
}

.ai-messages {
  /* basis 0：在固定高度面板里可靠吃满剩余空间，而不是被内容撑高 */
  flex: 1 1 0;
  min-height: 0;
  overflow-x: hidden;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  /* 顶部堆叠，禁止把气泡纵向拉伸填满容器 */
  align-items: stretch;
  justify-content: flex-start;
  gap: 10px;
  margin: 0;
  padding-right: 4px;
  scrollbar-gutter: stable;
}

/* 对话历史：覆盖在消息区上方，不挤占输入框 */
.ai-history-panel {
  position: absolute;
  inset: 0;
  z-index: 4;
  display: flex;
  flex-direction: column;
  min-height: 0;
  border: 1px solid var(--line);
  background: rgba(255, 252, 246, 0.97);
  box-shadow: 0 12px 36px rgba(39, 30, 18, 0.14);
  backdrop-filter: blur(10px);
}

.ai-history-panel[hidden] {
  display: none !important;
}

.ai-history-toolbar {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
}

.ai-history-label {
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.ai-history-list {
  flex: 1 1 0;
  min-height: 0;
  overflow: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 10px;
  scrollbar-gutter: stable;
}

.ai-history-empty {
  margin: 18px 8px;
  color: var(--muted);
  font-size: var(--fs-md);
  line-height: 1.55;
  text-align: center;
}

.ai-history-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  align-items: start;
  border: 1px solid transparent;
  padding: 4px 4px 4px 6px;
  background: rgba(255, 249, 238, 0.55);
  transition: border-color 140ms ease, background 140ms ease;
}

.ai-history-item:hover {
  border-color: var(--line);
  background: #fff8ed;
}

.ai-history-item.active {
  border-color: rgba(182, 64, 43, 0.45);
  background: #fff8ed;
  box-shadow: inset 3px 0 0 var(--accent);
}

.ai-history-main {
  min-width: 0;
  display: grid;
  gap: 4px;
  border: 0;
  padding: 8px 6px;
  background: transparent;
  color: inherit;
  cursor: pointer;
  text-align: left;
}

.ai-history-title {
  overflow: hidden;
  color: var(--ink);
  font-size: var(--fs-md);
  font-weight: 700;
  line-height: 1.4;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ai-history-meta {
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  line-height: 1.4;
}

.ai-history-preview {
  overflow: hidden;
  color: var(--muted);
  font-size: var(--fs-sm);
  line-height: 1.45;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ai-history-delete {
  flex: 0 0 auto;
  border: 1px solid transparent;
  padding: 5px 9px;
  background: transparent;
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  text-transform: uppercase;
}

.ai-history-delete:hover {
  border-color: rgba(163, 51, 51, 0.35);
  background: rgba(163, 51, 51, 0.06);
  color: #6e1f1f;
}

.ai-welcome {
  flex: 0 0 auto;
  border: 1px dashed var(--line);
  padding: 14px 12px;
  color: var(--muted);
  font-size: var(--fs-base);
  line-height: 1.65;
}

.ai-welcome p {
  margin: 0 0 0.55em;
}

.ai-welcome p:last-child {
  margin-bottom: 0;
}

/* 气泡高度完全由内容决定；禁止被 flex 父级压缩/拉伸 */
.ai-bubble {
  box-sizing: border-box;
  flex: 0 0 auto;
  align-self: flex-start;
  width: fit-content;
  max-width: 100%;
  height: auto;
  min-height: 0;
  border: 1px solid var(--line);
  padding: 12px 14px;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: var(--fs-base);
  line-height: 1.65;
  overflow: visible;
}

.ai-bubble.user {
  align-self: flex-end;
  width: fit-content;
  max-width: 92%;
  border-color: rgba(182, 64, 43, 0.35);
  background: #fff8ed;
  box-shadow: inset 3px 0 0 var(--accent);
}

.ai-bubble.assistant,
.ai-bubble.error {
  align-self: stretch;
  width: 100%;
  max-width: 100%;
  background: rgba(255, 252, 246, 0.9);
}

.ai-bubble.error {
  border-color: rgba(163, 51, 51, 0.4);
  background: rgba(163, 51, 51, 0.06);
  color: #6e1f1f;
}

.ai-bubble .ai-role {
  display: block;
  margin: 0 0 6px;
  color: var(--accent-dark);
  font-family: "Courier New", monospace;
  font-size: var(--fs-2xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.25;
  text-transform: uppercase;
}

.ai-bubble .ai-text {
  display: block;
  width: 100%;
  height: auto;
  margin: 0;
  padding: 0;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  word-break: break-word;
  line-height: 1.55;
}

/* 助手 Markdown：复用 .markdown-body 语义，尺寸按聊天气泡收紧 */
.ai-bubble .ai-text.markdown-body,
.ai-bubble .ai-text.ai-md {
  white-space: normal;
  font-size: var(--fs-base);
  line-height: 1.65;
}

.ai-bubble .ai-text.markdown-body > :first-child {
  margin-top: 0;
}

.ai-bubble .ai-text.markdown-body > :last-child {
  margin-bottom: 0;
}

.ai-bubble .ai-text.markdown-body h1,
.ai-bubble .ai-text.markdown-body h2,
.ai-bubble .ai-text.markdown-body h3,
.ai-bubble .ai-text.markdown-body h4,
.ai-bubble .ai-text.markdown-body h5,
.ai-bubble .ai-text.markdown-body h6 {
  margin: 0.85em 0 0.4em;
  scroll-margin-top: 0;
  line-height: 1.25;
}

.ai-bubble .ai-text.markdown-body h1 {
  font-size: 1.28em;
}

.ai-bubble .ai-text.markdown-body h2 {
  padding-top: 0.35em;
  border-top: 1px solid var(--line);
  font-size: 1.16em;
}

.ai-bubble .ai-text.markdown-body h2:first-child {
  padding-top: 0;
  border-top: 0;
}

.ai-bubble .ai-text.markdown-body h3 {
  font-size: 1.08em;
}

.ai-bubble .ai-text.markdown-body h4,
.ai-bubble .ai-text.markdown-body h5,
.ai-bubble .ai-text.markdown-body h6 {
  font-size: 1em;
}

.ai-bubble .ai-text.markdown-body p {
  margin: 0 0 0.7em;
}

.ai-bubble .ai-text.markdown-body ul,
.ai-bubble .ai-text.markdown-body ol {
  margin: 0 0 0.7em;
  padding-left: 1.25em;
}

.ai-bubble .ai-text.markdown-body li {
  margin: 0.22em 0;
}

.ai-bubble .ai-text.markdown-body blockquote {
  margin: 0.7em 0;
  padding: 0.45em 0.8em;
}

.ai-bubble .ai-text.markdown-body .code-block {
  margin: 0.7em 0;
  box-shadow: none;
}

.ai-bubble .ai-text.markdown-body .code-block pre {
  padding: 10px 12px;
  padding-top: 32px;
  font-size: var(--fs-sm);
  line-height: 1.55;
}

.ai-bubble .ai-text.markdown-body .code-copy-btn {
  top: 6px;
  right: 6px;
  width: 24px;
  height: 24px;
  border-radius: 6px;
  /* 右侧对话区较窄，复制按钮常显更易点 */
  opacity: 0.88;
  pointer-events: auto;
  transform: none;
}

.ai-bubble .ai-text.markdown-body .code-copy-icon {
  width: 13px;
  height: 13px;
}

.ai-bubble .ai-text.markdown-body pre {
  margin: 0.7em 0;
  padding: 10px 12px;
  box-shadow: none;
  font-size: var(--fs-sm);
  line-height: 1.55;
}

.ai-bubble .ai-text.markdown-body code {
  font-size: 0.92em;
}

.ai-bubble .ai-text.markdown-body .table-wrap {
  margin: 0.7em 0;
}

.ai-bubble .ai-text.markdown-body table {
  min-width: 0;
  font-size: 0.92em;
}

.ai-bubble .ai-text.markdown-body th,
.ai-bubble .ai-text.markdown-body td {
  padding: 6px 8px;
}

.ai-bubble .ai-text.markdown-body hr {
  margin: 0.85em 0;
}

.ai-bubble .ai-text.markdown-body img {
  margin: 0.4em 0;
}


.ai-bubble.streaming .ai-text::after {
  content: "▍";
  margin-left: 2px;
  color: var(--accent);
  animation: ai-cursor 900ms steps(1) infinite;
}

@keyframes ai-cursor {
  50% {
    opacity: 0;
  }
}

.ai-form {
  flex: 0 0 auto;
  display: grid;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.ai-input-label {
  color: var(--muted);
  font-family: "Courier New", monospace;
  font-size: var(--fs-xs);
  font-weight: 700;
  text-transform: uppercase;
}

.ai-form textarea {
  box-sizing: border-box;
  display: block;
  width: 100%;
  height: 96px;
  min-height: 80px;
  max-height: 180px;
  resize: vertical;
  border: 1px solid var(--line);
  padding: 12px 14px;
  outline: none;
  background: rgba(255, 249, 238, 0.72);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: var(--fs-base);
  line-height: 1.55;
  overflow-y: auto;
  field-sizing: fixed;
}

.ai-form textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(182, 64, 43, 0.12);
}

.ai-form-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.ai-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--muted);
  font-size: var(--fs-sm);
  cursor: pointer;
  user-select: none;
}

.ai-toggle input {
  accent-color: var(--accent);
}

.ai-send {
  border: 1px solid var(--ink);
  padding: 10px 18px;
  background: var(--ink);
  color: #fff9ef;
  font-family: "Courier New", monospace;
  font-size: var(--fs-sm);
  font-weight: 700;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 140ms ease, background 140ms ease;
}

.ai-send:hover:not(:disabled) {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  transform: translateY(-1px);
}

.ai-send:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

@media (max-width: 1280px) {
  .shell {
    grid-template-columns:
      clamp(200px, 20vw, 260px)
      minmax(0, 1fr)
      clamp(260px, 24vw, 340px);
    gap: 14px;
  }

  .reader-scroll {
    padding: 28px clamp(16px, 3vw, 36px) 40px;
  }

  .reader-body {
    grid-template-columns: 1fr;
  }

  .toc-panel {
    position: relative;
    top: auto;
    max-height: none;
    order: -1;
  }

  .reader-status {
    width: min(280px, calc(100% - 28px));
    right: 14px;
    bottom: 14px;
  }
}

@media (max-width: 1100px) {
  body {
    overflow: auto;
  }

  .shell {
    grid-template-columns: 1fr;
    grid-template-rows: none;
    width: calc(100vw - 24px);
    max-width: none;
    height: auto;
    max-height: none;
    margin: 12px auto 24px;
    overflow: visible;
  }

  .library-panel,
  .reader,
  .ai-panel {
    height: auto;
    max-height: none;
    overflow: visible;
  }

  .library-panel {
    max-height: 40vh;
    overflow: hidden;
  }

  .library-panel .doc-list {
    overflow: auto;
  }

  .reader {
    /* 窄屏阅读区给固定可视高度，内部 scroll + 右下角浮层仍可用 */
    height: min(70dvh, 720px);
    max-height: min(70dvh, 720px);
    overflow: hidden;
  }

  .reader-scroll {
    padding: 26px 18px 40px;
  }

  .reader-topline {
    display: grid;
  }

  .raw-link {
    width: max-content;
  }

  .reader-status {
    padding: 10px 12px 12px;
    width: min(260px, calc(100% - 24px));
    right: 12px;
    bottom: 12px;
  }

  .reader-body {
    padding-bottom: 12px;
  }

  /* 窄屏：给对话区固定可视高度，消息区内部滚动 */
  .ai-panel {
    height: min(62dvh, 520px);
    max-height: min(62dvh, 520px);
    overflow: hidden;
  }
}

@media (max-width: 900px) {
  .shell {
    width: calc(100vw - 16px);
    gap: 12px;
  }

  .reader-scroll {
    padding: 22px 14px 36px;
  }

  .reader-status {
    left: 12px;
    right: 12px;
    width: auto;
    bottom: 12px;
  }

  .reader-status__meta {
    gap: 6px;
  }
}
/* Mermaid 流程图：与暖纸阅读区协调，避免被当成深色代码块 */
.markdown-body .mermaid-block {
  position: relative;
  margin: 1.5em 0;
  padding: 1.1rem 1rem 0.85rem;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 14px;
  background:
    linear-gradient(180deg, rgba(255, 252, 246, 0.96), rgba(243, 232, 216, 0.88));
  box-shadow: 0 12px 36px rgba(39, 30, 18, 0.08);
}

.markdown-body .mermaid-block-label {
  position: absolute;
  top: 10px;
  left: 12px;
  color: var(--muted);
  font-family: "Cascadia Code", "Courier New", monospace;
  font-size: var(--fs-xs);
  letter-spacing: 0.04em;
  text-transform: lowercase;
  user-select: none;
  pointer-events: none;
}

.markdown-body .mermaid-block .mermaid,
.markdown-body .mermaid-block pre.mermaid {
  margin: 0.55rem 0 0;
  padding: 0.35rem 0.15rem 0.15rem;
  overflow: visible;
  border: 0;
  background: transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: var(--fs-base);
  line-height: 1.5;
  white-space: pre-wrap;
  text-align: center;
}

.markdown-body .mermaid-block svg {
  max-width: 100%;
  height: auto;
}

.markdown-body .mermaid-fallback {
  display: block;
  margin-top: 1.4rem;
  padding: 0.85rem 0.9rem;
  border: 1px dashed rgba(182, 64, 43, 0.35);
  border-radius: 10px;
  background: rgba(255, 249, 238, 0.7);
  color: var(--ink);
  text-align: left;
  white-space: pre-wrap;
}

.markdown-body .mermaid-fallback::before {
  content: attr(data-mermaid-error);
  display: block;
  margin-bottom: 0.55rem;
  color: var(--accent-dark);
  font-size: var(--fs-sm);
  font-family: "Cascadia Code", "Courier New", monospace;
}

.ai-bubble .ai-text.markdown-body .mermaid-block {
  margin: 0.85em 0;
  padding: 0.85rem 0.75rem 0.65rem;
  border-radius: 10px;
}