/* ============================================================
   寻迹 · 官网
   ------------------------------------------------------------
   设计概念：「朱批」

   页面是一张稿纸，AI 的声音以朱红批注的形式出现在页边。
   —— 中式校注传统里，先生用朱笔在旁批，学生在正文上改。
      正好对应产品里「AI 在稿纸上批注」这件事本身。

   视觉系统与产品「墨·书房」同源：
     宣纸底 · 墨色字 · 朱砂主色 · 泥金 / 竹青 / 琥珀点缀
   字体：思源宋体（Noto Serif SC）作标题与正文，
        霞鹜文楷（LXGW WenKai）作「手写批注」。
   ============================================================ */

/* ---------- 语义变量 ---------- */
:root,
html[data-theme='light'] {
  --paper-0: #faf7f0;
  --paper-1: #f3efe4;
  --paper-2: #ebe5d6;
  --paper-3: #e0d8c4;
  --paper-4: #d2c8ae;
  --paper-5: #b8ad8f;

  --ink-0: #2b2822;
  --ink-1: #4a463c;
  --ink-2: #756f5f;
  --ink-3: #a29a83;
  --ink-4: #c2b99f;

  --cinnabar: #b0402f;
  --cinnabar-bright: #c24a35;
  --cinnabar-soft: #d4705f;
  --cinnabar-dim: rgba(176, 64, 47, 0.09);
  --cinnabar-glow: rgba(176, 64, 47, 0.2);

  --gold: #96762c;
  --gold-dim: rgba(150, 118, 44, 0.1);
  --bamboo: #5c7d55;
  --bamboo-dim: rgba(92, 125, 85, 0.1);
  --amber: #9d7220;
  --amber-dim: rgba(157, 114, 32, 0.11);

  --bg-base: var(--paper-1);
  --bg-container: var(--paper-0);
  --bg-sunken: var(--paper-2);
  --bg-elevated: #fffdf8;
  --bg-hover: var(--paper-3);

  --text-primary: var(--ink-0);
  --text-secondary: var(--ink-1);
  --text-tertiary: var(--ink-2);
  --text-quaternary: var(--ink-3);

  --border: rgba(120, 108, 82, 0.16);
  --border-strong: rgba(120, 108, 82, 0.3);
  --border-faint: rgba(120, 108, 82, 0.09);

  --ruled-line: rgba(120, 108, 82, 0.075);
  --mark-bg: rgba(207, 161, 36, 0.28);
  --mark-text: #6d5316;

  --shadow-card: 0 1px 2px rgba(94, 82, 56, 0.05), 0 4px 14px rgba(94, 82, 56, 0.05);
  --shadow-float: 0 8px 28px rgba(94, 82, 56, 0.13);
  --shadow-lift: 0 2px 6px rgba(94, 82, 56, 0.08);

  --grain-opacity: 0.5;
  --sec-band: transparent;

  color-scheme: light;
}

html[data-theme='dark'] {
  --paper-0: #262320;
  --paper-1: #1e1c19;
  --paper-2: #28251f;
  --paper-3: #322e27;
  --paper-4: #403b32;
  --paper-5: #524c40;

  --ink-0: #ece5d6;
  --ink-1: #bdb5a4;
  --ink-2: #918a7a;
  --ink-3: #6b6558;
  --ink-4: #4c473d;

  --cinnabar: #d4624a;
  --cinnabar-bright: #e0715a;
  --cinnabar-soft: #b5513d;
  --cinnabar-dim: rgba(212, 98, 74, 0.13);
  --cinnabar-glow: rgba(212, 98, 74, 0.26);

  --gold: #c2a05a;
  --gold-dim: rgba(194, 160, 90, 0.13);
  --bamboo: #8bab84;
  --bamboo-dim: rgba(139, 171, 132, 0.13);
  --amber: #d0a44e;
  --amber-dim: rgba(208, 164, 78, 0.13);

  --bg-base: var(--paper-1);
  --bg-container: var(--paper-2);
  --bg-sunken: #191714;
  --bg-elevated: var(--paper-3);
  --bg-hover: var(--paper-4);

  --text-primary: var(--ink-0);
  --text-secondary: var(--ink-1);
  --text-tertiary: var(--ink-2);
  --text-quaternary: var(--ink-3);

  --border: rgba(236, 229, 214, 0.1);
  --border-strong: rgba(236, 229, 214, 0.2);
  --border-faint: rgba(236, 229, 214, 0.06);

  --ruled-line: rgba(236, 229, 214, 0.05);
  --mark-bg: rgba(192, 160, 90, 0.24);
  --mark-text: #e3c884;

  --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.24), 0 4px 14px rgba(0, 0, 0, 0.2);
  --shadow-float: 0 8px 28px rgba(0, 0, 0, 0.4);
  --shadow-lift: 0 2px 6px rgba(0, 0, 0, 0.3);

  --grain-opacity: 0.32;
  --sec-band: rgba(236, 229, 214, 0.022);

  color-scheme: dark;
}

/* ---------- 基础 ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: 'Noto Serif SC', 'Songti SC', 'SimSun', serif;
  font-size: 16px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* 纸纹：极淡的颗粒噪点，宣纸的手感 */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: var(--grain-opacity);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='4' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23n)' opacity='0.055'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

html[data-theme='dark'] body::before {
  mix-blend-mode: screen;
}

body > * {
  position: relative;
  z-index: 1;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  border: 0;
  background: none;
  cursor: pointer;
}

:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 3px;
  border-radius: 3px;
}

::selection {
  background: var(--cinnabar-glow);
  color: var(--text-primary);
}

/* ---------- 版心 ---------- */
.wrap {
  width: min(1180px, 100% - 48px);
  margin-inline: auto;
}

/* ============================================================
   顶栏
   ============================================================ */
.topbar {
  position: sticky;
  top: 0;
  z-index: 60;
  background: color-mix(in srgb, var(--bg-base) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(14px);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.24s ease, background 0.24s ease;
}

.topbar.is-stuck {
  border-bottom-color: var(--border);
}

.topbar-inner {
  display: flex;
  align-items: center;
  gap: 28px;
  height: 66px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 9px;
  flex-shrink: 0;
}

.brand-name {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.1em;
}

.brand-sub {
  font-size: 12px;
  color: var(--text-quaternary);
  letter-spacing: 0.06em;
}

.topnav {
  display: flex;
  gap: 26px;
  margin-left: auto;
}

.topnav a {
  position: relative;
  font-size: 14px;
  color: var(--text-tertiary);
  letter-spacing: 0.08em;
  padding: 4px 0;
  transition: color 0.18s ease;
}

.topnav a::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.26s cubic-bezier(0.22, 1, 0.36, 1);
}

.topnav a:hover {
  color: var(--text-primary);
}

.topnav a:hover::after {
  transform: scaleX(1);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-btn {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 9px;
  color: var(--text-tertiary);
  transition: background 0.18s ease, color 0.18s ease;
}

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

.icon-btn svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
}

.ico-moon {
  display: none;
}

html[data-theme='dark'] .ico-sun {
  display: none;
}

html[data-theme='dark'] .ico-moon {
  display: block;
}

.menu-btn {
  display: none;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: 10px;
  font-size: 14.5px;
  font-weight: 500;
  letter-spacing: 0.06em;
  white-space: nowrap;
  transition: transform 0.18s cubic-bezier(0.22, 1, 0.36, 1), background 0.18s ease,
    box-shadow 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 13.5px;
}

.btn-lg {
  padding: 14px 30px;
  font-size: 16px;
}

.btn-primary {
  background: var(--cinnabar);
  color: #fdfaf4;
  box-shadow: 0 2px 10px var(--cinnabar-glow);
}

html[data-theme='dark'] .btn-primary {
  color: #211d1a;
}

.btn-primary:hover {
  background: var(--cinnabar-bright);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--cinnabar-glow);
}

.btn-ghost {
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
}

.btn-ghost:hover {
  border-color: var(--cinnabar);
  color: var(--cinnabar);
  transform: translateY(-2px);
}

.btn-arrow {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  transition: transform 0.24s cubic-bezier(0.22, 1, 0.36, 1);
}

.btn:hover .btn-arrow {
  transform: translateX(3px);
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  position: relative;
  padding: 92px 0 84px;
  overflow: hidden;
}

/* 背景：稿纸横格 */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(
    to bottom,
    transparent 0 33px,
    var(--ruled-line) 33px 34px
  );
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.85), transparent 78%);
  -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.85), transparent 78%);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
  gap: 56px;
  align-items: center;
}

.eyebrow {
  margin: 0 0 22px;
  font-size: 12.5px;
  letter-spacing: 0.24em;
  color: var(--cinnabar);
  text-transform: uppercase;
}

.hero-title {
  margin: 0 0 26px;
  font-size: clamp(34px, 4.15vw, 54px);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: 0.015em;
  color: var(--text-primary);
}

/* 标题里被朱笔圈点的那几个字 */
.hero-title em {
  position: relative;
  font-style: normal;
  color: var(--cinnabar);
}

.hero-title em::after {
  content: '';
  position: absolute;
  left: -0.08em;
  right: -0.08em;
  bottom: 0.06em;
  height: 0.36em;
  background: var(--cinnabar-dim);
  border-radius: 2px;
  z-index: -1;
}

.hero-lede {
  margin: 0 0 38px;
  max-width: 34em;
  font-size: 16.5px;
  line-height: 2.05;
  color: var(--text-tertiary);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* ---------- 手稿窗口 ---------- */
/* 手稿占一格，朱批占右边一格「天头」——
   中式校注就是这么排的：正文一行行往下，批语在旁。 */
.hero-figure {
  margin: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 152px;
  gap: 0;
  align-items: end;
}

.ms-window {
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow-float);
  overflow: hidden;
}

.ms-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 11px 15px;
  border-bottom: 1px solid var(--border-faint);
  background: var(--bg-sunken);
}

.ms-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--paper-4);
}

.ms-title {
  margin-left: 10px;
  font-size: 12.5px;
  color: var(--text-tertiary);
  letter-spacing: 0.06em;
}

.ms-save {
  margin-left: auto;
  font-size: 11.5px;
  color: var(--bamboo);
  letter-spacing: 0.05em;
}

.ms-save::before {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-right: 6px;
  border-radius: 50%;
  background: var(--bamboo);
  vertical-align: middle;
}

.ms-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 208px;
}

.ms-editor {
  position: relative;
  padding: 26px 28px 34px;
  min-height: 258px;
  /* 稿纸横格 */
  background-image: repeating-linear-gradient(
    to bottom,
    transparent 0 29px,
    var(--ruled-line) 29px 30px
  );
  background-position: 0 20px;
}

.ms-p {
  margin: 0 0 16px;
  font-size: 14.5px;
  line-height: 2.05;
  color: var(--text-secondary);
  text-align: justify;
}

.ms-p-dim {
  color: var(--text-quaternary);
}

/* 选中的句子：黄铜标记底 + 朱笔圈点 */
.ms-sel {
  background: var(--mark-bg);
  box-shadow: 0 0 0 2px var(--mark-bg);
  border-radius: 2px;
  color: var(--mark-text);
  padding: 1px 1px;
  transition: background 0.3s ease, color 0.3s ease;
}

.ms-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 15px;
  height: 15px;
  margin-left: 3px;
  border-radius: 50%;
  background: var(--cinnabar);
  color: #fdfaf4;
  font-size: 9.5px;
  font-weight: 600;
  vertical-align: 0.42em;
  transform: translateY(-0.16em);
  line-height: 1;
}

html[data-theme='dark'] .ms-mark {
  color: #211d1a;
}

/* 行内工具条 */
.ms-toolbar {
  display: inline-flex;
  gap: 1px;
  margin-top: 4px;
  padding: 3px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 9px;
  box-shadow: var(--shadow-lift);
}

.ms-toolbar button {
  padding: 5px 12px;
  border-radius: 6px;
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  transition: background 0.16s ease, color 0.16s ease;
}

.ms-toolbar button:hover {
  background: var(--cinnabar);
  color: #fdfaf4;
}

html[data-theme='dark'] .ms-toolbar button:hover {
  color: #211d1a;
}

/* AI 侧栏 */
.ms-side {
  display: flex;
  flex-direction: column;
  border-left: 1px solid var(--border-faint);
  background: var(--bg-sunken);
  padding: 14px;
  gap: 12px;
}

.ms-roles {
  display: flex;
  gap: 4px;
}

.ms-role {
  flex: 1;
  text-align: center;
  padding: 4px 0;
  font-size: 11px;
  letter-spacing: 0.05em;
  color: var(--text-quaternary);
  border-bottom: 1.5px solid transparent;
  transition: color 0.18s ease, border-color 0.24s cubic-bezier(0.22, 1, 0.36, 1);
}

.ms-role.is-on {
  color: var(--cinnabar);
  border-bottom-color: var(--cinnabar);
}

.ms-msg {
  flex: 1;
  padding: 11px 12px;
  background: var(--bg-container);
  border: 1px solid var(--border-faint);
  border-radius: 9px;
}

.ms-msg-who {
  margin: 0 0 5px;
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--cinnabar);
}

.ms-msg-body {
  margin: 0;
  font-size: 12.5px;
  line-height: 1.9;
  color: var(--text-tertiary);
}

.ms-input {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 11px;
  border: 1px solid var(--border);
  border-radius: 9px;
  font-size: 12.5px;
  color: var(--text-quaternary);
}

.ms-input svg {
  width: 14px;
  height: 14px;
  margin-left: auto;
  fill: none;
  stroke: var(--cinnabar);
  stroke-width: 1.8;
}

.ms-foot {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 9px 16px;
  border-top: 1px solid var(--border-faint);
  background: var(--bg-sunken);
  font-size: 11.5px;
  color: var(--text-quaternary);
  letter-spacing: 0.05em;
}

.ms-dotsep {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--paper-4);
}

.ms-foot-right {
  margin-left: auto;
}

/* ---------- 朱批 ---------- */
.zhu {
  font-family: 'LXGW WenKai Screen', 'LXGW WenKai', 'Kaiti SC', 'KaiTi', cursive;
  font-size: 14px;
  line-height: 1.95;
  color: var(--cinnabar);
  letter-spacing: 0.03em;
}

.zhu[data-side='right'] {
  position: relative;
  align-self: center;
  padding: 0 0 0 13px;
}

.zhu[data-side='right'] .zhu-line {
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: var(--cinnabar);
  opacity: 0.42;
}

/* 朱笔落笔的横尾 */
.zhu[data-side='right'] .zhu-line::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 9px;
  height: 1px;
  background: var(--cinnabar);
  opacity: 0.42;
}

.zhu-inline {
  padding-left: 13px;
  border-left: 1px solid var(--cinnabar);
  opacity: 0.85;
  font-size: 13.5px;
}

.zhu-red {
  color: var(--cinnabar);
  position: relative;
}

/* ============================================================
   事实条
   ============================================================ */
.facts {
  border-block: 1px solid var(--border);
  background: var(--sec-band);
}

.facts-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
}

.fact {
  padding: 40px 30px;
  border-left: 1px solid var(--border-faint);
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.fact:first-child {
  border-left: 0;
}

.fact-num {
  font-size: 42px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--cinnabar);
}

.fact-label {
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--text-primary);
}

.fact-desc {
  font-size: 12.5px;
  color: var(--text-quaternary);
  letter-spacing: 0.04em;
}

/* ============================================================
   通用段落
   ============================================================ */
.sec {
  padding: 108px 0;
  position: relative;
}

.sec-alt {
  background: var(--sec-band);
  border-block: 1px solid var(--border-faint);
}

.sec-head {
  display: flex;
  gap: 30px;
  align-items: flex-start;
  margin-bottom: 58px;
}

/* 章节序号：朱笔题号 */
.sec-mark {
  flex-shrink: 0;
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  font-family: 'LXGW WenKai Screen', 'Kaiti SC', cursive;
  font-size: 25px;
  color: var(--cinnabar);
  border: 1px solid var(--cinnabar);
  border-radius: 8px;
  background: var(--cinnabar-dim);
  line-height: 1;
}

.sec-title {
  margin: 0 0 14px;
  font-size: clamp(27px, 3.1vw, 37px);
  font-weight: 700;
  line-height: 1.42;
  letter-spacing: 0.02em;
}

.sec-lede {
  margin: 0;
  max-width: 42em;
  font-size: 16px;
  line-height: 2;
  color: var(--text-tertiary);
}

/* ============================================================
   壹 · 五个角色
   ============================================================ */
.role-row {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
}

.role-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  gap: 14px;
  padding: 30px 12px 24px;
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.26s cubic-bezier(0.22, 1, 0.36, 1), border-color 0.2s ease,
    box-shadow 0.26s ease;
}

.role-card::before {
  content: '';
  position: absolute;
  inset: auto 0 0 0;
  height: 2px;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.role-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: var(--border-strong);
}

.role-card.is-on {
  border-color: var(--cinnabar);
  background: var(--bg-elevated);
  box-shadow: var(--shadow-card);
}

.role-card.is-on::before {
  transform: scaleX(1);
}

/* 竖排角色名：底端对齐，五张卡的字都站在同一条线上 */
.role-vert {
  writing-mode: vertical-rl;
  font-family: 'LXGW WenKai Screen', 'Kaiti SC', cursive;
  font-size: 25px;
  letter-spacing: 0.32em;
  color: var(--text-primary);
  line-height: 1;
  transition: color 0.2s ease;
}

.role-card.is-on .role-vert {
  color: var(--cinnabar);
}

.role-duty {
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--text-quaternary);
  text-align: center;
}

.role-detail {
  margin-top: 22px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 34px;
  align-items: center;
  padding: 30px 34px;
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-left: 2px solid var(--cinnabar);
  border-radius: 12px;
}

.role-detail-name {
  margin: 0 0 8px;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--cinnabar);
}

.role-detail-desc {
  margin: 0 0 20px;
  font-size: 14.5px;
  line-height: 1.95;
  color: var(--text-tertiary);
  max-width: 40em;
}

.role-params {
  display: flex;
  gap: 44px;
  margin: 0;
}

.role-params div {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.role-params dt {
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--text-quaternary);
}

.role-params dd {
  margin: 0;
  font-size: 14.5px;
  font-weight: 600;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--text-primary);
}

.role-detail .zhu-inline {
  align-self: stretch;
  display: flex;
  align-items: center;
}

/* ============================================================
   貳 · 双通道
   ============================================================ */
.duo {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.duo-card {
  padding: 34px 34px 30px;
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 14px;
  transition: transform 0.26s cubic-bezier(0.22, 1, 0.36, 1), box-shadow 0.26s ease;
}

.duo-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
}

.duo-head {
  margin-bottom: 22px;
  padding-bottom: 20px;
  border-bottom: 1px dashed var(--border);
}

.duo-tag {
  display: inline-block;
  margin-bottom: 12px;
  padding: 3px 12px;
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--cinnabar);
  background: var(--cinnabar-dim);
  border-radius: 4px;
}

.duo-head h3 {
  margin: 0 0 6px;
  font-size: 21px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.duo-head p {
  margin: 0;
  font-size: 14px;
  color: var(--text-quaternary);
}

.duo-list {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
}

.duo-list li {
  padding: 8px 0;
  font-size: 14.5px;
  color: var(--text-tertiary);
  border-bottom: 1px solid var(--border-faint);
}

.duo-list li:last-child {
  border-bottom: 0;
}

.duo-list b {
  display: inline-block;
  min-width: 5.2em;
  margin-right: 10px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.06em;
}

.duo-scope {
  margin: 0;
  padding: 11px 14px;
  font-size: 12.5px;
  line-height: 1.85;
  color: var(--text-quaternary);
  background: var(--bg-sunken);
  border-radius: 8px;
}

.duo-scope::before {
  content: '上下文 ';
  color: var(--cinnabar);
  letter-spacing: 0.08em;
}

/* ============================================================
   叁 · 素材
   ============================================================ */
.mat-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  gap: 56px;
  align-items: start;
}

.flow {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: flow;
}

.flow li {
  position: relative;
  counter-increment: flow;
  padding: 0 0 26px 52px;
}

.flow li:last-child {
  padding-bottom: 0;
}

/* 竖线串起四个步骤 */
.flow li::before {
  content: counter(flow, cjk-ideographic);
  position: absolute;
  left: 0;
  top: 0;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  font-size: 13px;
  color: var(--cinnabar);
  background: var(--cinnabar-dim);
  border: 1px solid var(--cinnabar-glow);
  border-radius: 50%;
}

.flow li:not(:last-child)::after {
  content: '';
  position: absolute;
  left: 15.5px;
  top: 38px;
  bottom: 6px;
  width: 1px;
  background: var(--border);
}

.flow b {
  display: block;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.flow span {
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--text-quaternary);
}

/* 对话演示 */
.mat-demo {
  padding: 28px;
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow-card);
}

.chat-q {
  display: inline-block;
  margin-bottom: 18px;
  padding: 9px 16px;
  background: var(--cinnabar);
  color: #fdfaf4;
  font-size: 14.5px;
  border-radius: 12px 12px 12px 3px;
  max-width: 88%;
}

html[data-theme='dark'] .chat-q {
  color: #211d1a;
}

.chat-a {
  padding: 20px 22px;
  background: var(--bg-sunken);
  border-radius: 12px 12px 3px 12px;
  border: 1px solid var(--border-faint);
}

.chat-a p {
  margin: 0 0 16px;
  font-size: 14.5px;
  line-height: 2;
  color: var(--text-secondary);
}

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

.cite {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 11px;
  font-size: 12.5px;
  color: var(--text-tertiary);
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 7px;
  transition: border-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.cite:hover {
  border-color: var(--cinnabar);
  color: var(--cinnabar);
  transform: translateY(-2px);
}

.cite-tag {
  padding: 1px 6px;
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--gold);
  background: var(--gold-dim);
  border-radius: 3px;
}

.cite-tag-pdf {
  color: var(--bamboo);
  background: var(--bamboo-dim);
}

.cite-tag-web {
  color: var(--amber);
  background: var(--amber-dim);
}

.cite-page {
  color: var(--text-quaternary);
  font-size: 11.5px;
}

.mat-demo .zhu-inline {
  margin: 20px 0 0;
}

/* ============================================================
   肆 · 长篇工程
   ============================================================ */
.lf-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.lf-card {
  padding: 30px 32px 26px;
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 14px;
}

.lf-card h3 {
  margin: 0 0 6px;
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.06em;
}

.lf-card > p {
  margin: 0 0 20px;
  font-size: 13.5px;
  line-height: 1.9;
  color: var(--text-quaternary);
}

.lf-foot {
  margin: 16px 0 0 !important;
  font-size: 12px !important;
  color: var(--text-quaternary) !important;
  letter-spacing: 0.05em;
}

/* 一致性问题条目 */
.issues {
  list-style: none;
  margin: 0;
  padding: 0;
}

.issues li {
  display: flex;
  align-items: flex-start;
  gap: 11px;
  padding: 9px 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--text-tertiary);
  border-bottom: 1px solid var(--border-faint);
}

.issues li:last-child {
  border-bottom: 0;
}

.sev {
  flex-shrink: 0;
  margin-top: 3px;
  padding: 1px 8px;
  font-size: 10.5px;
  letter-spacing: 0.06em;
  border-radius: 3px;
}

.sev-hi {
  color: var(--cinnabar);
  background: var(--cinnabar-dim);
}

.sev-mid {
  color: var(--amber);
  background: var(--amber-dim);
}

.sev-lo {
  color: var(--text-quaternary);
  background: var(--bg-sunken);
}

/* 版本列表 */
.vers {
  list-style: none;
  margin: 0;
  padding: 0;
}

.vers li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px 0;
  font-size: 13.5px;
  color: var(--text-tertiary);
  border-bottom: 1px solid var(--border-faint);
}

.vers li:last-child {
  border-bottom: 0;
}

.vers b {
  flex-shrink: 0;
  width: 34px;
  text-align: center;
  padding: 2px 0;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--text-quaternary);
  background: var(--bg-sunken);
  border-radius: 4px;
}

.vers .is-now b {
  color: var(--cinnabar);
  background: var(--cinnabar-dim);
}

/* 进度曲线 */
.spark {
  width: 100%;
  height: auto;
  margin-top: 4px;
}

.spark-fill {
  fill: url(#sg);
}

.spark-line {
  fill: none;
  stroke: var(--cinnabar);
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* 情节卡看板 */
.kanban {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.kb-col {
  padding: 9px;
  background: var(--bg-sunken);
  border-radius: 8px;
  border: 1px solid var(--border-faint);
}

.kb-h {
  display: block;
  margin-bottom: 7px;
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--text-quaternary);
}

.kb-card {
  display: block;
  padding: 7px 9px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-tertiary);
  background: var(--bg-container);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.kb-card.is-on {
  border-color: var(--cinnabar);
  color: var(--cinnabar);
}

/* ============================================================
   伍 · 自留地
   ============================================================ */
.sec-dark {
  background: var(--paper-2);
  border-block: 1px solid var(--border);
  color: var(--text-primary);
}

html[data-theme='dark'] .sec-dark {
  background: #171512;
}

.own-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
}

.own-item {
  padding: 32px 28px;
  background: var(--paper-2);
  transition: background 0.24s ease;
}

html[data-theme='dark'] .own-item {
  background: #171512;
}

.own-item:hover {
  background: var(--paper-3);
}

.own-n {
  display: block;
  margin-bottom: 16px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--cinnabar);
  font-variant-numeric: tabular-nums;
}

.own-item h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.own-item p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--text-tertiary);
}

/* ============================================================
   CTA
   ============================================================ */
.cta {
  padding: 116px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

/* 底部一抹朱砂，像落款 */
.cta::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 190px;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cinnabar), transparent);
  opacity: 0.5;
}

.cta-kicker {
  margin: 0 0 18px;
  font-size: 12.5px;
  letter-spacing: 0.26em;
  color: var(--cinnabar);
}

.cta-title {
  margin: 0 0 24px;
  font-size: clamp(29px, 4vw, 46px);
  font-weight: 700;
  line-height: 1.45;
  letter-spacing: 0.02em;
}

.cta-sub {
  margin: 0 0 40px;
  font-size: 15.5px;
  line-height: 2.05;
  color: var(--text-tertiary);
}

.cta-btns {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 14px;
}

/* ============================================================
   页脚
   ============================================================ */
.foot {
  border-top: 1px solid var(--border);
  padding: 34px 0 40px;
  background: var(--sec-band);
}

.foot-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.foot-brand {
  display: flex;
  align-items: baseline;
  gap: 9px;
}

.foot-note {
  margin: 0;
  font-size: 12.5px;
  color: var(--text-quaternary);
  letter-spacing: 0.04em;
}

.foot-links {
  display: flex;
  gap: 20px;
  margin-left: auto;
}

.foot-links a {
  font-size: 12.5px;
  color: var(--text-quaternary);
  letter-spacing: 0.08em;
  transition: color 0.18s ease;
}

.foot-links a:hover {
  color: var(--cinnabar);
}

/* ============================================================
   揭示动效
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.72s cubic-bezier(0.22, 1, 0.36, 1),
    transform 0.72s cubic-bezier(0.22, 1, 0.36, 1);
  transition-delay: var(--d, 0s);
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1080px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 52px;
  }
  .hero-title {
    max-width: 18em;
  }
  .zhu[data-side='right'] {
    grid-column: 1 / -1;
    padding: 14px 0 0 13px;
    margin-top: 16px;
    border-left: 1px solid var(--cinnabar);
  }
  .zhu[data-side='right'] .zhu-line {
    display: none;
  }
  .hero-figure {
    grid-template-columns: minmax(0, 1fr);
  }
  .role-detail {
    grid-template-columns: 1fr;
    gap: 22px;
  }
  .mat-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .own-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 900px) {
  .topnav {
    display: none;
  }
  .topnav.is-open {
    display: flex;
    position: absolute;
    top: 66px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 8px 24px 18px;
    background: var(--bg-base);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-float);
  }
  .topnav.is-open a {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-faint);
  }
  .topnav.is-open a:last-child {
    border-bottom: 0;
  }
  .menu-btn {
    display: grid;
  }
  .topbar-actions {
    margin-left: auto;
  }
  .facts-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .fact:nth-child(3) {
    border-left: 0;
  }
  .fact:nth-child(n + 3) {
    border-top: 1px solid var(--border-faint);
  }
  .role-row {
    grid-template-columns: repeat(3, 1fr);
  }
  .duo,
  .lf-grid {
    grid-template-columns: 1fr;
  }
  .sec {
    padding: 78px 0;
  }
}

@media (max-width: 620px) {
  .wrap {
    width: min(1180px, 100% - 32px);
  }
  /* 窄屏藏掉品牌副标题与「进入书房」文字，给导航留住空间 */
  .brand-sub {
    display: none;
  }
  .topbar-inner {
    gap: 12px;
  }
  .topbar-actions {
    gap: 6px;
  }
  .topbar-actions .btn-sm {
    padding: 8px 12px;
  }
  .hero {
    padding: 56px 0 60px;
  }
  .ms-body {
    grid-template-columns: 1fr;
  }
  .ms-side {
    border-left: 0;
    border-top: 1px solid var(--border-faint);
  }
  .ms-editor {
    padding: 20px 18px 26px;
  }
  .fact {
    padding: 26px 18px;
  }
  .fact-num {
    font-size: 32px;
  }
  .role-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  .role-vert {
    font-size: 22px;
  }
  .role-params {
    flex-wrap: wrap;
    gap: 20px 30px;
  }
  .sec-head {
    gap: 18px;
  }
  .sec-mark {
    width: 42px;
    height: 42px;
    font-size: 20px;
  }
  .own-grid {
    grid-template-columns: 1fr;
  }
  .duo-card,
  .lf-card,
  .mat-demo {
    padding: 24px 20px;
  }
  .kanban {
    grid-template-columns: 1fr;
  }
  .foot-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }
  .foot-links {
    margin-left: 0;
  }
}