:root {
  --bg: #f3efe6;
  --paper: #fbf8f2;
  --ink: #1e2430;
  --muted: #5f6b7a;
  --line: rgba(30, 36, 48, 0.12);
  --accent: #0e5a61;
  --accent-2: #b54f2d;
  --accent-soft: rgba(14, 90, 97, 0.11);
  --warm: rgba(181, 79, 45, 0.1);
  --shadow: 0 18px 45px rgba(31, 38, 52, 0.08);
  --sidebar-w: 320px;
  --radius: 22px;
  --code: "Cascadia Code", "Fira Code", Consolas, monospace;
  --body: Georgia, "Times New Roman", serif;
  --ui: "Segoe UI", Tahoma, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: var(--body);
  background:
    radial-gradient(circle at top left, rgba(181, 79, 45, 0.12), transparent 28%),
    radial-gradient(circle at bottom right, rgba(14, 90, 97, 0.12), transparent 26%),
    linear-gradient(180deg, #efe8da 0%, var(--bg) 48%, #f7f3eb 100%);
}

button,
input {
  font: inherit;
}

.shell {
  display: grid;
  grid-template-columns: minmax(280px, var(--sidebar-w)) 1fr;
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  padding: 28px 24px;
  border-right: 1px solid var(--line);
  background: rgba(251, 248, 242, 0.86);
  backdrop-filter: blur(12px);
}

.brand,
.controls,
nav {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.brand,
.controls {
  padding: 18px;
  margin-bottom: 18px;
}

.eyebrow,
.nav-label,
.field span {
  font-family: var(--ui);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

.brand h1,
.hero h2,
.section-card h3 {
  margin: 10px 0 0;
  line-height: 1.05;
}

.brand h1 {
  font-size: 32px;
}

.brand.brand-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 180px;
}

.brand-logo-img {
  display: block;
  width: 100%;
  max-width: 220px;
  height: auto;
  object-fit: contain;
}

.muted,
.hero-lead,
.hero-note,
.section-meta,
.section-card p,
.section-card li {
  color: var(--muted);
}

.field {
  display: grid;
  gap: 8px;
}

.field input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: #fff;
}

.lang-switch {
  display: flex;
  gap: 8px;
  margin-top: 14px;
}

.lang-switch button {
  flex: 1;
  padding: 11px 10px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  font-family: var(--ui);
  font-weight: 700;
  cursor: pointer;
}

.lang-switch button.active {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

.quick-links {
  margin-top: 14px;
  display: flex;
  gap: 8px;
}

.quick-links a {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--ui);
  font-weight: 700;
}

nav {
  padding: 18px 14px 12px;
  overflow: auto;
  max-height: calc(100vh - 295px);
}

.nav-list {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.nav-list a {
  display: block;
  padding: 10px 12px;
  text-decoration: none;
  color: var(--ink);
  border-radius: 14px;
  font-family: var(--ui);
}

.nav-list a:hover,
.nav-list a:focus {
  background: var(--accent-soft);
  outline: none;
}

.content {
  padding: 36px;
}

.sidebar-block {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
  margin-bottom: 18px;
}

.page-intro h2,
.page-intro p {
  margin-top: 0;
}

.page-intro h2 {
  font-size: clamp(28px, 3vw, 44px);
}

.sidebar-links,
.toc-list {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.sidebar-links a,
.toc-list a {
  display: block;
  padding: 10px 12px;
  text-decoration: none;
  color: var(--ink);
  border-radius: 14px;
  font-family: var(--ui);
}

.sidebar-links a:hover,
.sidebar-links a:focus,
.toc-list a:hover,
.toc-list a:focus {
  background: var(--accent-soft);
  outline: none;
}

.volume-link.active {
  background: var(--ink);
  color: #fff;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 34px;
  border: 1px solid var(--line);
  border-radius: 30px;
  background:
    linear-gradient(135deg, rgba(14, 90, 97, 0.08), transparent 55%),
    linear-gradient(160deg, rgba(181, 79, 45, 0.12), rgba(255, 255, 255, 0.78)),
    var(--paper);
  box-shadow: var(--shadow);
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto -50px -50px auto;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: var(--warm);
}

.hero h2 {
  font-size: clamp(36px, 4vw, 64px);
  max-width: 880px;
}

.hero-lead {
  max-width: 900px;
  font-size: 20px;
  line-height: 1.6;
}

.hero-note {
  margin-top: 18px;
  max-width: 820px;
  padding: 14px 16px;
  border-left: 4px solid var(--accent-2);
  background: rgba(255, 255, 255, 0.55);
  font-family: var(--ui);
}

.section-list {
  display: grid;
  gap: 18px;
  margin-top: 22px;
}

.detail-links {
  margin-top: 22px;
}

.detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

.detail-card {
  display: grid;
  gap: 8px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fffdfa;
  color: var(--ink);
  text-decoration: none;
  transition: transform 120ms ease, border-color 120ms ease, background 120ms ease;
}

.detail-card:hover,
.detail-card:focus {
  transform: translateY(-2px);
  border-color: rgba(14, 90, 97, 0.35);
  background: rgba(14, 90, 97, 0.05);
  outline: none;
}

.detail-card strong {
  font-family: var(--ui);
  font-size: 16px;
}

.detail-card span {
  color: var(--muted);
  line-height: 1.55;
}

.section-card {
  padding: 24px;
  border-radius: 26px;
  border: 1px solid var(--line);
  background: var(--paper);
  box-shadow: var(--shadow);
}

.section-card header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 14px;
  align-items: baseline;
  margin-bottom: 16px;
}

.section-card h3 {
  font-size: 30px;
}

.section-meta {
  font-family: var(--ui);
  font-size: 13px;
}

.section-card p,
.section-card li {
  font-size: 18px;
  line-height: 1.72;
}

.section-card ul {
  margin: 12px 0 0;
  padding-left: 22px;
}

.section-card code {
  font-family: var(--code);
  font-size: 0.88em;
  color: var(--accent-2);
}

.section-card .tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.section-card .source-list,
.section-card .callout-list {
  margin: 16px 0 0;
  padding-left: 20px;
  color: var(--muted);
}

.section-card pre {
  margin: 16px 0 0;
  padding: 16px 18px;
  overflow: auto;
  border-radius: 18px;
  border: 1px solid var(--line);
  background: #f4efe6;
}

.section-card pre code {
  display: block;
  color: var(--ink);
  font-family: var(--code);
  font-size: 14px;
  line-height: 1.6;
  white-space: pre;
}

.diagram-card {
  margin-top: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background:
    linear-gradient(180deg, rgba(14, 90, 97, 0.06), rgba(255, 255, 255, 0.7)),
    #fffdfa;
}

.diagram-title {
  margin: 0 0 12px;
  font-family: var(--ui);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}

.diagram-card .mermaid {
  margin: 0;
  padding: 8px;
  overflow-x: auto;
  background: transparent;
  border: 0;
}

.doc-table-wrap {
  margin-top: 16px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 18px;
}

.doc-table {
  width: 100%;
  border-collapse: collapse;
  background: #fffdfa;
  font-family: var(--ui);
}

.doc-table th,
.doc-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
  font-size: 14px;
  line-height: 1.55;
}

.doc-table th {
  color: var(--accent);
  background: rgba(14, 90, 97, 0.06);
}

.section-card .tag {
  padding: 6px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-family: var(--ui);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

@media (max-width: 960px) {
  .shell {
    grid-template-columns: 1fr;
  }

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

  nav {
    max-height: none;
  }

  .content {
    padding: 18px;
  }

  .hero,
  .section-card {
    padding: 22px;
  }
}