:root {
  --color-surface: #fbfbfb;
  --color-surface-alt: #f2f2f2;
  --color-surface-deep: #e5e6e6;
  --color-ink: #42494d;
  --color-ink-soft: #677075;
  --color-ink-muted: #798286;
  --color-line: #dadbdc;
  --color-primary: #447b97;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e1e9ed;
  --color-accent: #0a8571;
  --color-accent-ink: #ffffff;
  --color-highlight: #d0e6e2;
  --color-focus: #027d69;
  --color-contrast-surface: #151a1d;
  --color-contrast-ink: #e4e6e7;
  --color-contrast-line: #434749;
  --color-contrast-accent: #11eec9;
  --overlay-scrim: linear-gradient(180deg, rgba(21, 26, 29, 0.35) 0%, rgba(21, 26, 29, 0.72) 55%, rgba(21, 26, 29, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 11.0px;
  --text-sm: 14.7px;
  --text-base: 17px;
  --text-lg: 22.7px;
  --text-xl: 30.2px;
  --text-2xl: 40.3px;
  --text-3xl: 53.7px;
  --text-4xl: 71.5px;
  --text-display: clamp(35px, 7.1vw, 91px);
  --text-figure: clamp(29px, 5.2vw, 66px);
  --weight-heading: 728;
  --weight-body: 400;
  --leading-body: 1.78;
  --leading-heading: 1.27;
  --tracking-heading: 0.005em;
  --radius-sm: 14px;
  --radius-md: 15px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(66, 73, 77, 0.08);
  --shadow-2: 0 18px 44px rgba(66, 73, 77, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1300px;
  --measure: 74ch;
  --gutter: 32px;
  --section-y: 76px;
  --section-y-lg: 106px;
}

/* ===========================================================
   1. Reset 与基础
   =========================================================== */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  word-break: break-word;
  line-break: normal;
}

body.nav-open { overflow: hidden; }

img, svg, video, canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

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

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  text-wrap: balance;
}

p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }

a {
  color: var(--color-primary);
  text-decoration-thickness: var(--border-thin);
  text-underline-offset: 3px;
  transition: color 0.18s ease;
}
a:hover { color: var(--color-accent); }

::selection {
  background: var(--color-highlight);
  color: var(--color-accent);
}

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

.section--dark :focus-visible,
.bento-block--dark :focus-visible,
.site-footer :focus-visible {
  outline-color: var(--color-contrast-accent);
}

.skip-link {
  position: absolute;
  left: var(--space-2);
  top: calc(-1 * var(--space-8));
  z-index: 200;
  padding: 10px 18px;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  box-shadow: var(--shadow-2);
  transition: top 0.2s ease;
}
.skip-link:focus { top: var(--space-2); color: var(--color-accent-ink); }

/* ===========================================================
   2. 排版工具
   =========================================================== */
.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: -0.015em;
  margin: 0;
}

.figure-num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
}

.prose {
  max-width: var(--measure);
  color: var(--color-ink);
}
.prose > * + * { margin-top: var(--space-3); }
.prose h2 { font-size: var(--text-xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-4); }
.prose p { margin: 0; }
.prose a { color: var(--color-primary); }
.prose a:hover { color: var(--color-accent); }
.prose strong { font-weight: var(--weight-heading); }

.block-kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-2);
}

.block-title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  margin: 0 0 var(--space-1);
}

.block-note {
  font-size: var(--text-sm);
  line-height: 1.65;
  color: var(--color-ink-soft);
  margin: 0;
}

.section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
  transition: color 0.3s ease;
}

[data-chapter][data-inview="true"] .section-index { color: var(--color-accent); }

.section--dark .section-index,
.bento-block--dark .section-index { color: var(--color-contrast-accent); }

.chapter-head {
  display: grid;
  grid-template-columns: minmax(0, auto) minmax(0, 1fr);
  gap: var(--space-3);
  align-items: start;
  margin-bottom: var(--space-4);
}

.chapter-title {
  font-size: var(--text-2xl);
  margin: 0 0 var(--space-1);
}

.chapter-desc {
  max-width: var(--measure);
  font-size: var(--text-base);
  color: var(--color-ink-soft);
  margin: 0;
}

.section--dark .chapter-desc,
.bento-block--dark .chapter-desc { color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent); }

/* ===========================================================
   3. 布局：容器 / 区块 / 栅格
   =========================================================== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: var(--section-y); position: relative; }
.section--lg { padding-block: var(--section-y-lg); }
.section--alt { background: var(--color-surface-alt); }
.section--deep { background: var(--color-surface-deep); }
.section--dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--dark h1,
.section--dark h2,
.section--dark h3 { color: var(--color-contrast-ink); }
.section--dark .prose { color: var(--color-contrast-ink); }
.section--dark .prose a { color: var(--color-contrast-accent); }
.section--dark .block-note,
.section--dark .stat-label { color: color-mix(in srgb, var(--color-contrast-ink) 74%, transparent); }
.section--dark .block-kicker { color: var(--color-contrast-accent); }

.section--first { padding-top: calc(var(--space-8) + 88px); }

.hero {
  position: relative;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding-top: calc(var(--space-8) + 88px);
  padding-bottom: var(--section-y-lg);
  overflow: hidden;
}
.hero h1, .hero h2, .hero h3 { color: var(--color-contrast-ink); }

/* ===========================================================
   4. 按钮 / 标签
   =========================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 11px 20px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease,
              background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  box-shadow: var(--shadow-1);
}
.btn-primary:hover {
  color: var(--color-primary-ink);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.btn-accent {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  box-shadow: var(--shadow-1);
}
.btn-accent:hover {
  color: var(--color-accent-ink);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.btn-ghost {
  background: transparent;
  color: inherit;
  border-color: currentColor;
}
.btn-ghost:hover {
  color: inherit;
  background: color-mix(in srgb, currentColor 14%, transparent);
  transform: translateY(-2px);
}

.btn-dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  box-shadow: var(--shadow-1);
}
.btn-dark:hover {
  color: var(--color-contrast-ink);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.btn-sm { padding: 8px 16px; font-size: var(--text-sm); }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 13px;
  border-radius: var(--radius-pill);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.4;
}
.chip--accent { background: var(--color-highlight); color: var(--color-accent); }
.chip--dark {
  background: color-mix(in srgb, var(--color-contrast-accent) 20%, transparent);
  color: var(--color-contrast-accent);
}

/* ===========================================================
   5. 动效与显现（reduced-motion 见文末）
   =========================================================== */
[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
[data-reveal][data-revealed="true"] {
  opacity: 1;
  transform: translateY(0);
}

/* ===========================================================
   6. 头部
   =========================================================== */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 60;
  color: var(--color-contrast-ink);
  background-color: transparent;
  background-image: linear-gradient(180deg, color-mix(in srgb, var(--color-contrast-surface) 68%, transparent), transparent);
  border-bottom: var(--border-thin) solid transparent;
  transition: background-color 0.28s ease, color 0.28s ease,
              box-shadow 0.28s ease, border-color 0.28s ease;

  --brand-sub-ink: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
  --nav-idx-ink: var(--color-contrast-accent);
  --nav-hover-bg: color-mix(in srgb, var(--color-contrast-ink) 14%, transparent);
  --nav-current-bg: color-mix(in srgb, var(--color-contrast-accent) 18%, transparent);
  --nav-current-ink: var(--color-contrast-ink);
}

.site-header[data-scrolled="true"],
.site-header[data-variant="solid"] {
  color: var(--color-ink);
  background-color: var(--color-surface);
  background-image: none;
  box-shadow: var(--shadow-1);
  border-bottom-color: var(--color-line);

  --brand-sub-ink: var(--color-ink-muted);
  --nav-idx-ink: var(--color-ink-muted);
  --nav-hover-bg: color-mix(in srgb, var(--color-ink) 9%, transparent);
  --nav-current-bg: var(--color-primary-soft);
  --nav-current-ink: var(--color-primary);
}

.header-inner {
  position: relative;
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-3) var(--gutter);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: inherit;
  flex: 0 0 auto;
}
.brand:hover { color: inherit; }

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  transform: skewX(-8deg);
}

.brand-mark-glyph {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 700;
  font-style: normal;
  line-height: 1;
  transform: skewX(8deg);
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.15;
}

.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  letter-spacing: 0.015em;
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.07em;
  color: var(--brand-sub-ink);
}

.site-nav { margin-left: auto; }

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid transparent;
  color: inherit;
  text-decoration: none;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.25;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.nav-link:hover {
  color: inherit;
  background: var(--nav-hover-bg);
}
.nav-link[aria-current="page"] {
  background: var(--nav-current-bg);
  color: var(--nav-current-ink);
  border-color: color-mix(in srgb, var(--nav-current-ink) 34%, transparent);
}

.nav-idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--nav-idx-ink);
}

.nav-label { display: block; }

.nav-quick { display: none; }

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-left: var(--space-1);
  flex: 0 0 auto;
}

.scroll-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--color-contrast-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 0.15s linear, background-color 0.28s ease;
}
.site-header[data-scrolled="true"] .scroll-progress,
.site-header[data-variant="solid"] .scroll-progress { background: var(--color-accent); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 14px;
  border: var(--border-thin) solid currentColor;
  border-radius: var(--radius-pill);
  color: inherit;
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  background: transparent;
}
.nav-toggle:hover { background: var(--nav-hover-bg); }

.nav-toggle-icon {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
}
.nav-toggle-bar {
  display: block;
  width: 16px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: currentColor;
  transition: transform 0.22s ease, opacity 0.22s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:first-child {
  transform: translateY(3px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

/* ===========================================================
   7. 页脚（卡片式）
   =========================================================== */
.site-footer {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding-block: var(--section-y) var(--space-4);
}

.footer-inner {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--space-2);
}

.footer-card {
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-contrast-line);
  background: color-mix(in srgb, var(--color-contrast-ink) 6%, var(--color-contrast-surface));
  padding: var(--space-3);
  box-shadow: var(--shadow-1);
}

.footer-card--brand { grid-column: span 3; }
.footer-card--links { grid-column: span 2; }
.footer-card--contact {
  grid-column: span 3;
  background: var(--color-accent);
  border-color: transparent;
  color: var(--color-accent-ink);
  box-shadow: var(--shadow-2);
}

.footer-brand {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  margin: 0 0 var(--space-1);
}

.footer-line {
  font-size: var(--text-sm);
  line-height: 1.7;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
  margin: 0 0 var(--space-3);
}

.footer-meta { display: grid; gap: var(--space-1); }

.footer-meta-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  padding-bottom: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}
.footer-meta-item:last-child { border-bottom: 0; padding-bottom: 0; }

.footer-meta-key {
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-meta-val {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-contrast-accent);
}

.footer-card-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
  margin: 0 0 var(--space-2);
}
.footer-card--contact .footer-card-title { color: color-mix(in srgb, var(--color-accent-ink) 82%, transparent); }

.footer-links { display: grid; gap: var(--space-1); }
.footer-links a {
  display: inline-block;
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}
.footer-links a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: currentColor;
}

.footer-contact { display: grid; gap: var(--space-2); margin-bottom: var(--space-3); }
.footer-contact-item { display: grid; gap: 2px; }
.footer-contact-key {
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: color-mix(in srgb, var(--color-accent-ink) 74%, transparent);
}
.footer-contact-val {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-accent-ink);
  word-break: break-all;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  margin-top: var(--space-4);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 64%, transparent);
}

.footer-icp { font-family: var(--font-mono); letter-spacing: 0.05em; }
.footer-addr { flex: 1 1 320px; }
.footer-copy { font-family: var(--font-mono); }

.to-top {
  margin-left: auto;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-contrast-line);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-xs);
  font-weight: 600;
  cursor: pointer;
  box-shadow: var(--shadow-2);
  transition: color 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}
.to-top:hover {
  color: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
  transform: translateY(-2px);
}

/* ===========================================================
   8. Bento 模块板
   =========================================================== */
.bento {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--space-3);
}

.bento-block {
  grid-column: span 4;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface);
  box-shadow: var(--shadow-1);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.bento-block:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-2);
  border-color: color-mix(in srgb, var(--color-primary) 48%, var(--color-line));
}

.bento-block--quarter { grid-column: span 3; }
.bento-block--third { grid-column: span 4; }
.bento-block--half { grid-column: span 6; }
.bento-block--wide { grid-column: span 8; }
.bento-block--full { grid-column: span 12; }
.bento-block--tall { grid-row: span 2; }

.bento-block--primary {
  background: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 24%, var(--color-primary-soft));
}

.bento-block--focus {
  background: var(--color-accent);
  border-color: transparent;
  color: var(--color-accent-ink);
  box-shadow: var(--shadow-2);
}
.bento-block--focus:hover { border-color: color-mix(in srgb, var(--color-accent-ink) 40%, transparent); }
.bento-block--focus .block-note,
.bento-block--focus .stat-label { color: color-mix(in srgb, var(--color-accent-ink) 82%, transparent); }
.bento-block--focus .block-kicker { color: color-mix(in srgb, var(--color-accent-ink) 78%, transparent); }
.bento-block--focus .data-row { border-bottom-color: color-mix(in srgb, var(--color-accent-ink) 28%, transparent); }
.bento-block--focus .data-key,
.bento-block--focus .data-val { color: var(--color-accent-ink); }

.bento-block--dark {
  background: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.bento-block--dark .block-title { color: var(--color-contrast-ink); }
.bento-block--dark .block-note,
.bento-block--dark .stat-label { color: color-mix(in srgb, var(--color-contrast-ink) 74%, transparent); }
.bento-block--dark .block-kicker { color: var(--color-contrast-accent); }
.bento-block--dark .data-row { border-bottom-color: var(--color-contrast-line); }
.bento-block--dark .data-key { color: color-mix(in srgb, var(--color-contrast-ink) 70%, transparent); }
.bento-block--dark .data-val { color: var(--color-contrast-ink); }

/* ===========================================================
   9. 数据 / 指标 / 路径
   =========================================================== */
.data-list { display: grid; }

.data-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-1) 0;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.data-row:last-child { border-bottom: 0; padding-bottom: 0; }

.data-key { font-size: var(--text-sm); color: var(--color-ink-soft); }

.data-val {
  font-family: var(--font-mono);
  font-size: var(--text-base);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.stat { display: flex; flex-direction: column; gap: 4px; }

.stat-value {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
}
.bento-block--focus .stat-value { color: var(--color-accent-ink); }
.bento-block--dark .stat-value { color: var(--color-contrast-accent); }

.stat-label { font-size: var(--text-sm); color: var(--color-ink-soft); }

.path-tree { display: grid; gap: 0; }

.path-node {
  position: relative;
  padding: 0 0 var(--space-3) var(--space-4);
  border-left: var(--border-thick) solid var(--color-line);
}
.path-node:last-child { border-left-color: transparent; padding-bottom: 0; }

.path-node::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 6px;
  width: 9px;
  height: 9px;
  border-radius: var(--radius-pill);
  background: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-surface);
}

.section--alt .path-node::before { box-shadow: 0 0 0 4px var(--color-surface-alt); }

.path-node-title {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  margin: 0 0 4px;
}

/* ===========================================================
   10. 图片容器（页面阶段放占位图）
   =========================================================== */
.image-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-md);
  background: var(--color-surface-deep);
  aspect-ratio: 16 / 9;
  box-shadow: var(--shadow-1);
}

.image-frame--4x3 { aspect-ratio: 4 / 3; }
.image-frame--1x1 { aspect-ratio: 1 / 1; }
.image-frame--wide { aspect-ratio: 21 / 9; }

.image-frame__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.image-frame__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.image-frame__caption {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.5;
  margin: 0;
}

/* ===========================================================
   11. 面包屑
   =========================================================== */
.breadcrumb { padding-block: var(--space-3) 0; }

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0 var(--space-1);
  font-size: var(--text-sm);
}

.breadcrumb-item { display: inline-flex; align-items: center; }
.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: var(--space-1);
  color: var(--color-ink-muted);
  font-family: var(--font-mono);
}

.breadcrumb-item a {
  color: var(--color-ink-soft);
  text-decoration: none;
}
.breadcrumb-item a:hover { color: var(--color-primary); text-decoration: underline; }

.breadcrumb-current { color: var(--color-ink); font-weight: 600; }

.section--dark .breadcrumb-item a,
.section--dark .breadcrumb-current { color: var(--color-contrast-ink); }
.section--dark .breadcrumb-item + .breadcrumb-item::before { color: var(--color-contrast-line); }

/* ===========================================================
   12. 响应式
   =========================================================== */
@media (max-width: 1280px) {
  .header-ghost { display: none; }
}

@media (max-width: 1100px) {
  .header-inner {
    padding: var(--space-2) var(--space-3);
    gap: var(--space-2);
  }
  .header-actions { margin-left: auto; }
  .nav-toggle { display: inline-flex; position: relative; z-index: 90; }
  .brand-sub { display: none; }

  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(86vw, 400px);
    margin: 0;
    padding: calc(var(--space-8) + var(--space-2)) var(--space-3) var(--space-6);
    background: var(--color-contrast-surface);
    color: var(--color-contrast-ink);
    border-left: var(--border-thin) solid var(--color-contrast-line);
    box-shadow: var(--shadow-2);
    overflow-y: auto;
    transform: translateX(102%);
    transition: transform 0.3s ease;
    z-index: 70;

    --nav-hover-bg: color-mix(in srgb, var(--color-contrast-ink) 14%, transparent);
    --nav-current-bg: color-mix(in srgb, var(--color-contrast-accent) 18%, transparent);
    --nav-current-ink: var(--color-contrast-ink);
    --nav-idx-ink: var(--color-contrast-accent);
  }
  .site-nav[data-open] { transform: translateX(0); }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-link {
    flex-direction: row;
    align-items: baseline;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-1);
    border-radius: 0;
    border-bottom: var(--border-thin) solid var(--color-contrast-line);
    font-size: var(--text-lg);
  }
  .nav-link[aria-current="page"] {
    border-radius: var(--radius-sm);
    border-color: transparent;
  }
  .nav-idx { font-size: var(--text-xs); }

  .nav-quick {
    display: grid;
    gap: var(--space-1);
    margin-top: var(--space-4);
    padding-top: var(--space-3);
    border-top: var(--border-thin) solid var(--color-contrast-line);
  }
  .nav-quick .btn { width: 100%; }
  .nav-quick .btn-ghost { color: var(--color-contrast-ink); }

  .footer-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .footer-card--brand { grid-column: span 4; }
  .footer-card--links { grid-column: span 2; }
  .footer-card--contact { grid-column: span 4; }
}

@media (max-width: 900px) {
  .bento-block,
  .bento-block--third { grid-column: span 6; }
  .bento-block--quarter { grid-column: span 3; }
  .bento-block--wide { grid-column: span 12; }
  .bento-block--half { grid-column: span 6; }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-card--brand { grid-column: span 2; }
  .footer-card--links { grid-column: span 1; }
  .footer-card--contact { grid-column: span 2; }
}

@media (max-width: 640px) {
  :root { --gutter: 20px; }

  .section { padding-block: calc(var(--section-y) * 0.72); }
  .section--lg { padding-block: calc(var(--section-y-lg) * 0.72); }
  .section--first { padding-top: calc(var(--space-8) + 76px); }
  .hero { padding-top: calc(var(--space-8) + 76px); padding-bottom: var(--section-y); }

  .bento { gap: var(--space-2); }
  .bento-block,
  .bento-block--quarter,
  .bento-block--third,
  .bento-block--half,
  .bento-block--wide { grid-column: span 12; }
  .bento-block { padding: var(--space-3); }

  .chapter-head { grid-template-columns: minmax(0, 1fr); gap: var(--space-1); }

  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-card--brand,
  .footer-card--links,
  .footer-card--contact { grid-column: span 1; }

  .footer-base { flex-direction: column; align-items: flex-start; }
  .to-top { margin-left: 0; }

  .header-actions .btn-accent { padding: 8px 14px; }
  .nav-toggle-text { display: none; }
}

/* ===========================================================
   13. Reduced motion
   =========================================================== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  [data-reveal] { opacity: 1; transform: none; }
  .bento-block:hover { transform: none; }
  .btn:hover { transform: none; }
}