:root {
  color-scheme: light;
  --paper: #f8f4ea;
  --paper-strong: #fffdf7;
  --ink: #1d2521;
  --muted: #66716c;
  --line: #d9d0bf;
  --line-strong: #b6a88e;
  --accent: #0a6f74;
  --accent-strong: #074f54;
  --accent-warm: #b84b2a;
  --code-bg: #18211f;
  --code-ink: #eef3e7;
  --shadow: 0 18px 42px rgba(56, 44, 25, 0.11);
  --mono: "SFMono-Regular", "Cascadia Code", "Liberation Mono", Menlo, monospace;
  --body: "Avenir Next", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: Georgia, "Songti SC", "SimSun", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(90deg, rgba(10, 111, 116, 0.045) 1px, transparent 1px) 0 0 / 42px 42px,
    linear-gradient(rgba(184, 75, 42, 0.04) 1px, transparent 1px) 0 0 / 42px 42px,
    var(--paper);
  color: var(--ink);
  font-family: var(--body);
  line-height: 1.7;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-strong);
}

.site-frame {
  display: grid;
  grid-template-columns: 288px minmax(0, 1fr) 272px;
  min-height: 100vh;
}

.side-nav,
.outline {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  padding: 28px 22px;
}

.side-nav {
  border-right: 1px solid var(--line);
  background: rgba(248, 244, 234, 0.88);
  backdrop-filter: blur(18px);
}

.outline {
  border-left: 1px solid var(--line);
  background: rgba(255, 253, 247, 0.72);
}

.brand {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 12px;
  align-items: center;
  margin-bottom: 28px;
  color: var(--ink);
}

.brand-mark {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border: 2px solid var(--ink);
  background: var(--accent);
  color: #fffdf7;
  font-family: var(--display);
  font-weight: 700;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-family: var(--display);
  font-size: 1.18rem;
}

.brand small,
.nav-link small,
.source-path,
.eyebrow {
  color: var(--muted);
  font-size: 0.78rem;
}

.nav-group {
  margin: 0 0 24px;
}

.nav-group h2,
.outline h1,
.outline-group h2 {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-link {
  display: block;
  padding: 9px 10px;
  border-left: 3px solid transparent;
  color: var(--ink);
}

.nav-link span,
.nav-link small {
  display: block;
}

.nav-link small {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.is-active {
  border-color: var(--accent);
  background: rgba(10, 111, 116, 0.08);
}

.content {
  min-width: 0;
  padding: 34px min(5vw, 72px) 80px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.75fr);
  gap: 36px;
  align-items: stretch;
  min-height: 520px;
  padding: 46px;
  border: 1px solid var(--line-strong);
  background:
    linear-gradient(135deg, rgba(255, 253, 247, 0.98), rgba(255, 253, 247, 0.72)),
    repeating-linear-gradient(135deg, rgba(10, 111, 116, 0.09) 0 2px, transparent 2px 16px);
  box-shadow: var(--shadow);
}

.hero-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.eyebrow {
  margin: 0 0 10px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 820px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(3.1rem, 6vw, 6.4rem);
  line-height: 0.98;
  letter-spacing: 0;
}

.lead {
  max-width: 780px;
  margin: 26px 0 0;
  color: #3f4a45;
  font-size: 1.12rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.primary-action,
.secondary-action,
.source-link,
.search-control button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--ink);
  padding: 8px 15px;
  font-weight: 800;
}

.primary-action {
  background: var(--ink);
  color: var(--paper-strong);
}

.primary-action:hover {
  color: var(--paper-strong);
}

.secondary-action,
.source-link,
.search-control button {
  background: transparent;
  color: var(--ink);
}

.protocol-map {
  display: flex;
  min-height: 360px;
  flex-direction: column;
  justify-content: center;
  gap: 18px;
}

.map-node {
  display: block;
  border: 1px solid var(--line-strong);
  background: var(--paper-strong);
  padding: 16px;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.93rem;
  box-shadow: 8px 8px 0 rgba(10, 111, 116, 0.13);
}

.map-node.root {
  border-color: var(--ink);
  background: var(--accent);
  color: #fffdf7;
  font-size: 1.05rem;
}

.map-branches {
  display: grid;
  gap: 12px;
}

.utility-panel,
.reading-route,
.doc-section {
  margin-top: 28px;
  border: 1px solid var(--line);
  background: rgba(255, 253, 247, 0.88);
  box-shadow: var(--shadow);
}

.utility-panel {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.6fr);
  gap: 22px;
  padding: 22px;
}

.search-box label {
  display: block;
  margin-bottom: 8px;
  font-weight: 800;
}

.search-control {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
}

.search-control input {
  min-width: 0;
  border: 1px solid var(--line-strong);
  background: #fffdf7;
  color: var(--ink);
  font: inherit;
  padding: 10px 12px;
}

.search-results {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.search-result {
  border-left: 3px solid var(--accent-warm);
  background: rgba(184, 75, 42, 0.07);
  padding: 8px 10px;
}

.search-result strong,
.search-result span {
  display: block;
}

.search-result span {
  color: var(--muted);
  font-size: 0.86rem;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.stat-grid div {
  border: 1px solid var(--line);
  background: rgba(10, 111, 116, 0.06);
  padding: 14px;
}

.stat-grid strong,
.stat-grid span {
  display: block;
}

.stat-grid strong {
  font-family: var(--display);
  font-size: 2rem;
  line-height: 1.1;
}

.stat-grid span {
  color: var(--muted);
  font-size: 0.86rem;
}

.reading-route {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 24px;
  padding: 28px;
}

.reading-route h2 {
  margin: 0;
  font-family: var(--display);
  font-size: 2rem;
}

.reading-route ol {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 22px;
}

.reading-route li {
  padding-left: 4px;
}

.reading-route a,
.reading-route span {
  display: block;
}

.reading-route a {
  font-weight: 800;
}

.doc-stack {
  display: grid;
  gap: 28px;
}

.doc-section {
  scroll-margin-top: 24px;
}

.doc-header {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  justify-content: space-between;
  padding: 28px 30px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(10, 111, 116, 0.09), transparent);
}

.doc-header h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2rem, 4vw, 3.4rem);
  letter-spacing: 0;
}

.doc-header p {
  max-width: 720px;
  margin: 8px 0 0;
  color: var(--muted);
}

.source-path {
  margin: 0;
  font-family: var(--mono);
}

.source-link {
  flex: 0 0 auto;
  font-size: 0.9rem;
}

.markdown-body {
  padding: 18px 30px 34px;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  scroll-margin-top: 18px;
  line-height: 1.22;
  letter-spacing: 0;
}

.markdown-body h1 {
  margin: 24px 0 12px;
  font-family: var(--display);
  font-size: 2.4rem;
}

.markdown-body h2 {
  margin: 34px 0 12px;
  border-top: 1px solid var(--line);
  padding-top: 20px;
  font-family: var(--display);
  font-size: 1.84rem;
}

.markdown-body h3 {
  margin: 26px 0 10px;
  font-size: 1.28rem;
}

.markdown-body h4 {
  margin: 22px 0 8px;
  font-size: 1.08rem;
}

.markdown-body p,
.markdown-body li {
  color: #36403b;
}

.markdown-body code,
.source-path {
  font-family: var(--mono);
}

.markdown-body :not(pre) > code {
  border: 1px solid rgba(10, 111, 116, 0.22);
  background: rgba(10, 111, 116, 0.08);
  padding: 0.1em 0.32em;
  color: #194f50;
  font-size: 0.88em;
}

.code-card {
  margin: 18px 0;
  overflow: hidden;
  border: 1px solid #2e3936;
  background: var(--code-bg);
}

.code-card figcaption {
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
  color: #b9c8c1;
  font-family: var(--mono);
  font-size: 0.76rem;
  padding: 8px 12px;
  text-transform: uppercase;
}

.code-card pre {
  margin: 0;
  overflow-x: auto;
  padding: 16px;
}

.code-card code {
  color: var(--code-ink);
  font-family: var(--mono);
  font-size: 0.9rem;
}

.table-wrap {
  margin: 18px 0;
  overflow-x: auto;
  border: 1px solid var(--line);
}

table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
  background: #fffdf7;
}

th,
td {
  border-bottom: 1px solid var(--line);
  border-right: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

th {
  background: rgba(10, 111, 116, 0.09);
  color: #17211e;
  font-size: 0.9rem;
}

tr:last-child td {
  border-bottom: 0;
}

th:last-child,
td:last-child {
  border-right: 0;
}

.anchor {
  display: inline-block;
  width: 1.1em;
  margin-left: -1.1em;
  color: transparent;
  font-family: var(--body);
  font-size: 0.76em;
}

h1:hover .anchor,
h2:hover .anchor,
h3:hover .anchor,
h4:hover .anchor {
  color: var(--accent-warm);
}

.outline-group {
  margin-bottom: 22px;
}

.outline-link {
  display: block;
  padding: 4px 0;
  color: #4a554f;
  font-size: 0.88rem;
}

.outline-link.level-3 {
  padding-left: 14px;
  font-size: 0.82rem;
}

.outline-link:hover {
  color: var(--accent);
}

.menu-toggle {
  display: none;
}

@media (max-width: 1180px) {
  .site-frame {
    grid-template-columns: 248px minmax(0, 1fr);
  }

  .outline {
    display: none;
  }

  .hero,
  .utility-panel,
  .reading-route {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 820px) {
  .site-frame {
    display: block;
  }

  .side-nav {
    position: static;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .side-nav nav {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 10px;
  }

  .nav-group {
    margin: 0;
  }

  .content {
    padding: 18px 14px 64px;
  }

  .hero,
  .utility-panel,
  .reading-route,
  .doc-header,
  .markdown-body {
    padding: 20px;
  }

  .hero {
    min-height: auto;
  }

  .hero h1 {
    font-size: 3.2rem;
  }

  .doc-header {
    display: block;
  }

  .source-link {
    margin-top: 14px;
  }

  .search-control,
  .stat-grid {
    grid-template-columns: 1fr;
  }
}