:root {
  --accent: #b45f47;
  --paper: #f7f5ef;
  --ink: #24231f;
  --body-font: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --heading-font: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --surface: color-mix(in srgb, var(--paper) 92%, white);
  --surface-strong: color-mix(in srgb, var(--paper) 82%, white);
  --muted: color-mix(in srgb, var(--ink) 58%, transparent);
  --faint: color-mix(in srgb, var(--ink) 7%, transparent);
  --border: color-mix(in srgb, var(--ink) 13%, transparent);
  --code-bg: color-mix(in srgb, var(--ink) 5%, var(--paper));
  --topbar-h: 64px;
  --sidebar-w: 276px;
  --outline-w: 224px;
  --article-w: 720px;
  color-scheme: light;
}

html[data-theme="dark"] {
  --paper: #1f1f1c;
  --ink: #ece8dd;
  --surface: #242420;
  --surface-strong: #2a2925;
  --muted: #aaa69c;
  --faint: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.13);
  --code-bg: #191916;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--topbar-h) + 24px);
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body-font);
  font-size: 15px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration-color: color-mix(in srgb, var(--accent) 55%, transparent); text-underline-offset: 3px; }
a:hover { color: var(--accent); }

button, input { font: inherit; }
button { color: inherit; }

.topbar {
  position: sticky;
  z-index: 40;
  top: 0;
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(18px);
}

.brand {
  min-width: 0;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 650;
  text-decoration: none;
  letter-spacing: -0.01em;
}

.brand small {
  padding-left: 10px;
  border-left: 1px solid var(--border);
  color: var(--muted);
  font-weight: 500;
}

.brand-mark {
  width: 22px;
  height: 22px;
  border: 1px solid var(--ink);
  border-radius: 50% 50% 48% 52%;
  box-shadow: inset 6px 0 0 var(--accent);
  transform: rotate(-9deg);
}

.brand-logo { width: 173px; height: 35px; object-fit: contain; object-position: left center; }

.top-actions { display: flex; align-items: center; gap: 8px; }

.search-trigger,
.theme-toggle,
.menu-toggle {
  min-height: 34px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  cursor: pointer;
}

.search-trigger {
  min-width: 190px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 0 9px 0 12px;
  color: var(--muted);
  text-align: left;
}

kbd {
  padding: 1px 6px;
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 5px;
  background: var(--paper);
  color: var(--muted);
  font-size: 11px;
}

.theme-toggle, .menu-toggle { width: 36px; padding: 0; }
.menu-toggle { display: none; }
.version { padding: 0 6px; color: var(--muted); font-size: 12px; }

.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--outline-w);
  min-height: calc(100vh - var(--topbar-h));
}

.sidebar,
.outline {
  position: sticky;
  top: var(--topbar-h);
  align-self: start;
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
  scrollbar-width: thin;
}

.sidebar {
  padding: 32px 20px 60px 24px;
  border-right: 1px solid var(--border);
}

.side-group { margin-bottom: 28px; }
.side-label {
  margin: 0 9px 8px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.side-link {
  display: block;
  padding: 6px 9px;
  border-radius: 6px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
  text-decoration: none;
}

.side-link:hover { background: var(--faint); color: var(--ink); }
.side-link.active { background: color-mix(in srgb, var(--accent) 10%, transparent); color: var(--accent); font-weight: 650; }

.content { min-width: 0; padding: 58px clamp(32px, 6vw, 92px) 96px; }
.article { max-width: var(--article-w); margin: 0 auto; }

.lead {
  margin: -4px 0 36px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.6;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--ink);
  font-family: var(--body-font);
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.025em;
}

h1 { margin: 0 0 22px; font-size: clamp(36px, 5vw, 52px); }
h2 { margin: 58px 0 18px; padding-top: 6px; font-size: 29px; }
h3 { margin: 34px 0 12px; font-family: var(--body-font); font-size: 19px; font-weight: 700; letter-spacing: -0.015em; }
h4 { margin: 28px 0 10px; font-family: var(--body-font); font-size: 16px; font-weight: 700; }

.heading-anchor {
  margin-left: 8px;
  color: transparent;
  font-family: var(--body-font);
  font-size: 0.65em;
  text-decoration: none;
}

h1:hover .heading-anchor, h2:hover .heading-anchor, h3:hover .heading-anchor { color: var(--border); }

p { margin: 0 0 18px; }
ul, ol { margin: 0 0 22px; padding-left: 24px; }
li { margin: 7px 0; padding-left: 4px; }
li::marker { color: var(--accent); }

blockquote {
  margin: 26px 0;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: var(--surface);
  color: color-mix(in srgb, var(--ink) 82%, transparent);
}

blockquote p:last-child { margin-bottom: 0; }

code {
  padding: 0.12em 0.34em;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--code-bg);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88em;
}

.code-block {
  position: relative;
  margin: 24px 0 28px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--code-bg);
}

.code-block pre { margin: 0; padding: 42px 18px 18px; overflow-x: auto; line-height: 1.58; }
.code-block pre code { padding: 0; border: 0; background: transparent; }
.code-label { position: absolute; top: 10px; left: 14px; color: var(--muted); font-size: 11px; text-transform: uppercase; }
.copy-code { position: absolute; top: 7px; right: 8px; padding: 3px 8px; border: 1px solid var(--border); border-radius: 5px; background: var(--surface); cursor: pointer; font-size: 11px; }

figure { margin: 30px 0; }
figure img {
  display: block;
  width: auto;
  max-width: 100%;
  height: auto;
  margin-inline: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  cursor: zoom-in;
}
figcaption { margin-top: 8px; color: var(--muted); font-size: 12px; text-align: center; }

.table-wrap { margin: 24px 0 28px; overflow-x: auto; border: 1px solid var(--border); border-radius: 8px; }
table { width: 100%; border-collapse: collapse; background: var(--surface); font-size: 13px; }
th, td { padding: 11px 13px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
th { background: var(--faint); font-weight: 700; }
tr:last-child td { border-bottom: 0; }
hr { margin: 52px 0; border: 0; border-top: 1px solid var(--border); }

.outline { padding: 42px 24px 60px 8px; }
.outline-title, .outline-empty { margin-bottom: 10px; color: var(--muted); font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; }
.outline-link { display: block; padding: 5px 0 5px 12px; border-left: 1px solid var(--border); color: var(--muted); font-size: 12px; line-height: 1.45; text-decoration: none; }
.outline-link.level-3 { padding-left: 24px; }
.outline-link:hover, .outline-link.active { border-left-color: var(--accent); color: var(--accent); }

.page-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 72px; padding-top: 22px; border-top: 1px solid var(--border); }
.pager { padding: 14px 16px; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); text-decoration: none; }
.pager span { display: block; margin-bottom: 2px; color: var(--muted); font-size: 11px; }
.pager.next { text-align: right; }

.search-dialog {
  position: fixed;
  z-index: 100;
  inset: 0;
  display: grid;
  place-items: start center;
  padding-top: min(14vh, 120px);
  background: rgba(20, 20, 18, 0.34);
  backdrop-filter: blur(8px);
}
.search-dialog[hidden] { display: none; }
.search-panel { width: min(640px, calc(100vw - 32px)); max-height: min(640px, 72vh); overflow: hidden auto; border: 1px solid var(--border); border-radius: 12px; background: var(--surface); box-shadow: 0 24px 80px rgba(0, 0, 0, 0.18); }
.search-input { position: sticky; top: 0; width: 100%; padding: 17px 18px; border: 0; border-bottom: 1px solid var(--border); outline: 0; background: var(--surface); color: var(--ink); font-size: 17px; }
.search-results { padding: 8px; }
.search-result { display: block; padding: 12px; border-radius: 7px; text-decoration: none; }
.search-result:hover { background: var(--faint); }
.search-result strong { display: block; margin-bottom: 3px; }
.search-result span { display: block; color: var(--muted); font-size: 12px; }
.search-empty { padding: 28px 14px; color: var(--muted); text-align: center; }

.image-dialog { max-width: 94vw; max-height: 94vh; padding: 0; border: 0; background: transparent; }
.image-dialog::backdrop { background: rgba(15, 15, 13, 0.78); backdrop-filter: blur(6px); }
.image-dialog img { display: block; max-width: 92vw; max-height: 90vh; border-radius: 8px; }
.image-dialog button { position: fixed; top: 18px; right: 22px; width: 38px; height: 38px; border: 1px solid rgba(255,255,255,.3); border-radius: 50%; background: rgba(0,0,0,.35); color: white; cursor: pointer; font-size: 22px; }

@media (max-width: 1080px) {
  .shell { grid-template-columns: var(--sidebar-w) minmax(0, 1fr); }
  .outline { display: none; }
}

@media (max-width: 760px) {
  :root { --topbar-h: 58px; }
  .topbar { padding: 0 14px; }
  .brand small, .version, .search-trigger span, .search-trigger kbd { display: none; }
  .search-trigger { min-width: 36px; width: 36px; padding: 0; }
  .search-trigger::before { content: "⌕"; width: 100%; text-align: center; font-size: 19px; }
  .menu-toggle { display: inline-block; }
  .shell { display: block; }
  .sidebar { position: fixed; z-index: 35; top: var(--topbar-h); bottom: 0; left: 0; width: min(86vw, 320px); height: auto; transform: translateX(-102%); background: var(--paper); box-shadow: 14px 0 44px rgba(0,0,0,.12); transition: transform .2s ease; }
  body.nav-open .sidebar { transform: translateX(0); }
  .content { padding: 38px 20px 72px; }
  h1 { font-size: 38px; }
  h2 { margin-top: 46px; font-size: 26px; }
  .page-nav { grid-template-columns: 1fr; }
}

.print-document { background: white; color: #222; }
.print-cover, .print-contents, .print-page { max-width: 760px; margin: 0 auto; padding: 64px 0; }
.print-cover { min-height: 88vh; display: flex; flex-direction: column; justify-content: center; }
.print-cover .eyebrow, .print-page-label { color: var(--accent); font-size: 11px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; }
.print-cover h1 { margin: 16px 0 12px; font-size: 64px; }
.print-cover p { color: #666; font-size: 22px; }
.print-contents li { margin: 9px 0; }
.print-page { border-top: 1px solid #ddd; }

@media print {
  :root { --paper: #fff; --ink: #222; --surface: #fff; --border: #d8d8d8; --code-bg: #f5f5f3; }
  @page { size: A4; margin: 18mm 17mm 20mm; }
  body { font-size: 10.5pt; print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  .topbar, .sidebar, .outline, .page-nav, .search-dialog, .image-dialog, .copy-code { display: none !important; }
  .shell { display: block; }
  .content { padding: 0; }
  .article { max-width: none; }
  h1, h2, h3 { break-after: avoid; }
  figure, table, pre, blockquote { break-inside: avoid; }
  a { color: inherit; text-decoration: none; }
  .print-cover { break-after: page; }
  .print-contents { break-after: page; }
  .print-page { max-width: none; padding: 0; border: 0; break-before: page; }
  .print-page:first-of-type { break-before: auto; }
  .print-page h1 { font-size: 30pt; }
  .code-block { overflow: visible; }
  .code-block pre { white-space: pre-wrap; word-break: break-word; }
}

/* Chapter metadata and historical navigation share the current theme. */
.chapter-meta { display: flex; align-items: center; flex-wrap: wrap; gap: 12px 24px; margin-bottom: 26px; color: var(--muted); font-size: 13px; }
.chapter-meta label { display: flex; align-items: center; gap: 8px; }
.chapter-version { max-width: 100%; padding: 5px 9px; border: 1px solid var(--border); border-radius: 6px; background: var(--surface); color: var(--ink); font: inherit; }
.history-notice { margin-bottom: 28px; padding: 12px 16px; border-left: 3px solid var(--accent); background: var(--surface-strong); }
.article { overflow-wrap: anywhere; }
.article pre { overflow-x: auto; }
.article table { display: block; overflow-x: auto; }
.image-dialog img { width: auto; height: auto; object-fit: contain; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
@media print { .chapter-meta label, .history-notice { display: none; } }
html[data-theme="dark"] .brand-logo { background: #f7f5ef; border-radius: 6px; padding: 4px 6px; }
@media (max-width: 760px) { .version { display: inline; padding: 0 2px; font-size: 11px; } }