:root {
  color-scheme: light;
  --page: #ffffff;
  --surface: #ffffff;
  --subtle: #f6f8fa;
  --ink: #1f2328;
  --muted: #656d76;
  --line: #d0d7de;
  --line-strong: #8c959f;
  --focus: #1f2328;
  --radius: 6px;
  --sidebar-width: 244px;
  --rail-width: 216px;
  --content-width: 860px;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif,
    "Apple Color Emoji", "Segoe UI Emoji";
  --font-code: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

button,
input {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--focus) 35%, transparent);
  outline-offset: 2px;
}

[hidden] {
  display: none !important;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 8px 12px;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  background: var(--page);
  color: var(--ink);
  font-weight: 600;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.topbar {
  display: none;
}

.site-shell {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, var(--content-width)) var(--rail-width);
  justify-content: center;
  min-height: 100dvh;
}

.sidebar {
  position: sticky;
  top: 0;
  display: flex;
  flex-direction: column;
  height: 100dvh;
  min-width: 0;
  padding: 28px 20px 20px;
  border-right: 1px solid var(--line);
  overflow-y: auto;
}

.sidebar-head {
  padding: 0 8px 22px;
}

.brand,
.compact-brand {
  display: inline-block;
  color: var(--ink);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  text-decoration: none;
}

.sidebar-head p {
  margin: 7px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.chapter-nav {
  display: grid;
  gap: 2px;
}

.chapter-link {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 8px;
  align-items: start;
  padding: 8px;
  border-radius: var(--radius);
  color: var(--muted);
  font-size: 14px;
  line-height: 1.35;
  text-decoration: none;
}

.chapter-link:hover {
  background: var(--subtle);
  color: var(--ink);
}

.chapter-link.is-active {
  background: var(--subtle);
  color: var(--ink);
  font-weight: 600;
}

.chapter-index {
  color: var(--muted);
  font-family: var(--font-code);
  font-size: 12px;
  line-height: 1.6;
}

.sidebar-tools {
  display: grid;
  gap: 6px;
  margin-top: auto;
  padding-top: 24px;
}

.tool-button,
.quiet-button,
.rail-action {
  min-height: 36px;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  line-height: 1.2;
  cursor: pointer;
}

.tool-button {
  width: 100%;
  text-align: left;
}

.tool-button:hover,
.quiet-button:hover,
.rail-action:hover {
  border-color: var(--line-strong);
  background: var(--subtle);
}

.main-content {
  width: 100%;
  min-width: 0;
  padding: 56px 64px 96px;
}

.page-rail {
  position: sticky;
  top: 0;
  align-self: start;
  max-height: 100dvh;
  padding: 56px 20px;
  border-left: 1px solid var(--line);
  overflow-y: auto;
}

.rail-title {
  margin: 0 0 10px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
}

.page-rail nav {
  display: grid;
  gap: 2px;
}

.page-rail nav a {
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  gap: 5px;
  padding: 5px 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.4;
  text-decoration: none;
}

.page-rail nav a:hover {
  color: var(--ink);
}

.page-rail nav a span {
  font-family: var(--font-code);
  font-size: 11px;
}

.rail-action {
  margin-top: 18px;
}

.page-header {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.document-label {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.4;
}

.page-header h1,
.home-title h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(34px, 4.2vw, 48px);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.12;
}

.page-lead,
.home-title > p:not(.document-label) {
  max-width: 680px;
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.6;
}

.local-toc {
  display: grid;
  gap: 4px;
  margin-top: 26px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--subtle);
}

.local-toc a {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 8px;
  color: var(--ink);
  font-size: 14px;
  line-height: 1.45;
  text-decoration: none;
}

.local-toc a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.local-toc a span {
  color: var(--muted);
  font-family: var(--font-code);
  font-size: 12px;
  line-height: 1.7;
}

.document-body {
  width: 100%;
}

.doc-section {
  padding: 42px 0 10px;
}

.doc-section + .doc-section {
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.doc-section h2,
.definition-block h2,
.chapter-section h2,
.principles h2,
.search-head h2 {
  margin: 0 0 18px;
  color: var(--ink);
  font-size: 28px;
  font-weight: 650;
  letter-spacing: -0.025em;
  line-height: 1.25;
}

.doc-section h2 span {
  color: var(--muted);
  font-family: var(--font-code);
  font-size: 0.72em;
  font-weight: 500;
}

.doc-section h3 {
  margin: 34px 0 10px;
  color: var(--ink);
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.01em;
  line-height: 1.35;
}

.doc-section p {
  margin: 0 0 16px;
}

.doc-section p,
.doc-section li,
.definition-block p,
.principle-grid p {
  max-width: 74ch;
}

.doc-section a {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.content-list {
  margin: 0 0 20px;
  padding-left: 28px;
}

.content-list li {
  margin: 4px 0;
  padding-left: 2px;
}

.content-list li::marker {
  color: var(--muted);
}

blockquote {
  margin: 18px 0;
  padding: 0 16px;
  border-left: 4px solid var(--line);
  color: var(--muted);
}

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

code {
  padding: 0.15em 0.35em;
  border-radius: 4px;
  background: var(--subtle);
  color: var(--ink);
  font-family: var(--font-code);
  font-size: 0.86em;
}

pre {
  margin: 18px 0 22px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--subtle);
  overflow: auto;
}

pre code {
  padding: 0;
  border-radius: 0;
  background: transparent;
  font-size: 13px;
  line-height: 1.55;
}

.page-turn {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.page-turn a {
  display: grid;
  gap: 2px;
  min-width: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
}

.page-turn a:hover {
  border-color: var(--line-strong);
  background: var(--subtle);
}

.page-turn a.next {
  text-align: right;
}

.page-turn span {
  color: var(--muted);
  font-size: 12px;
}

.page-turn strong {
  overflow: hidden;
  font-size: 14px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.home-hero {
  padding-bottom: 40px;
  border-bottom: 1px solid var(--line);
}

.home-title {
  max-width: 720px;
}

.primary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  margin-top: 24px;
  padding: 8px 14px;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  background: var(--ink);
  color: var(--page);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
}

.primary-action:hover {
  background: #3b4046;
}

.model-flow {
  display: grid;
  margin-top: 36px;
  border-top: 1px solid var(--line);
}

.model-flow div {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 8px;
  align-items: baseline;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}

.model-flow span,
.row-number,
.row-range {
  color: var(--muted);
  font-family: var(--font-code);
  font-size: 12px;
  font-weight: 400;
}

.model-flow strong {
  font-size: 14px;
  font-weight: 600;
}

.definition-block,
.chapter-section,
.principles {
  padding: 48px 0;
  border-bottom: 1px solid var(--line);
}

.definition-block {
  display: grid;
  gap: 24px;
}

.definition-block h2,
.chapter-section h2,
.principles h2 {
  margin-bottom: 10px;
}

.definition-block p,
.index-heading p {
  margin: 0;
  color: var(--muted);
}

.address-example {
  display: grid;
  gap: 5px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--subtle);
}

.address-example span {
  color: var(--muted);
  font-size: 12px;
}

.address-example strong {
  font-family: var(--font-code);
  font-size: 14px;
  font-weight: 600;
  overflow-wrap: anywhere;
}

.index-heading {
  margin-bottom: 22px;
}

.chapter-list {
  display: grid;
  border-top: 1px solid var(--line);
}

.chapter-row {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr) auto;
  gap: 12px;
  align-items: start;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}

.chapter-row:hover .row-copy strong {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.row-copy {
  display: grid;
  gap: 2px;
  min-width: 0;
}

.row-copy strong {
  font-size: 15px;
}

.row-copy small {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.row-range {
  padding-top: 2px;
}

.principle-grid {
  display: grid;
  gap: 14px;
  margin-top: 22px;
}

.principle-grid p {
  margin: 0;
}

.home-footer {
  padding: 32px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.home-footer strong {
  color: var(--ink);
  font-size: 15px;
}

.home-footer p {
  margin: 5px 0 0;
}

.search-dialog {
  width: min(640px, calc(100vw - 32px));
  max-height: min(720px, calc(100dvh - 32px));
  padding: 0;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--page);
  color: var(--ink);
}

.search-dialog::backdrop {
  background: rgb(31 35 40 / 0.45);
}

.search-head {
  display: flex;
  gap: 20px;
  align-items: start;
  justify-content: space-between;
  padding: 20px;
  border-bottom: 1px solid var(--line);
}

.search-head h2 {
  margin: 0;
  font-size: 20px;
}

.search-head p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.search-field {
  display: grid;
  gap: 6px;
  padding: 20px;
}

.search-field span {
  font-size: 13px;
  font-weight: 600;
}

.search-field input {
  width: 100%;
  min-height: 42px;
  padding: 8px 11px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--page);
  color: var(--ink);
}

.search-field input::placeholder {
  color: var(--muted);
}

.search-results {
  max-height: 430px;
  padding: 0 20px 20px;
  overflow-y: auto;
}

.search-result {
  display: grid;
  gap: 3px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  text-decoration: none;
}

.search-result:hover strong {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.search-result span,
.search-result small,
.search-empty {
  color: var(--muted);
  font-size: 12px;
}

.search-result strong {
  font-size: 14px;
}

.search-empty {
  margin: 0;
  padding: 12px 0;
}

.sidebar-backdrop {
  display: none;
}

@media (max-width: 1199px) {
  .site-shell {
    grid-template-columns: var(--sidebar-width) minmax(0, var(--content-width));
  }

  .page-rail {
    display: none;
  }
}

@media (max-width: 840px) {
  html {
    scroll-padding-top: 72px;
  }

  body {
    font-size: 15px;
  }

  body.menu-open {
    overflow: hidden;
  }

  .topbar {
    position: sticky;
    top: 0;
    z-index: 40;
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 56px;
    padding: 8px 16px;
    border-bottom: 1px solid var(--line);
    background: var(--page);
  }

  .topbar-actions {
    display: flex;
    gap: 6px;
  }

  .quiet-button {
    min-height: 34px;
    padding: 6px 9px;
  }

  .site-shell {
    display: block;
    min-height: auto;
  }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 60;
    width: min(320px, calc(100vw - 44px));
    height: 100dvh;
    padding-top: 24px;
    background: var(--page);
    transform: translateX(-102%);
    transition: transform 160ms ease;
  }

  .menu-open .sidebar {
    transform: translateX(0);
  }

  .sidebar-backdrop:not([hidden]) {
    position: fixed;
    inset: 0;
    z-index: 50;
    display: block;
    border: 0;
    background: rgb(31 35 40 / 0.45);
  }

  .main-content {
    max-width: 760px;
    margin-inline: auto;
    padding: 32px 20px 72px;
  }

  .page-header h1,
  .home-title h1 {
    font-size: 32px;
  }

  .page-lead,
  .home-title > p:not(.document-label) {
    font-size: 16px;
  }

  .doc-section {
    padding-top: 34px;
  }

  .doc-section + .doc-section {
    margin-top: 10px;
  }

  .doc-section h2,
  .definition-block h2,
  .chapter-section h2,
  .principles h2 {
    font-size: 24px;
  }

  .doc-section h3 {
    margin-top: 28px;
    font-size: 19px;
  }

  .definition-block,
  .chapter-section,
  .principles {
    padding: 38px 0;
  }
}

@media (max-width: 520px) {
  .main-content {
    padding-inline: 16px;
  }

  .compact-brand {
    font-size: 18px;
  }

  .page-header {
    padding-bottom: 26px;
  }

  .local-toc {
    padding: 14px;
  }

  .page-turn {
    grid-template-columns: 1fr;
  }

  .page-turn a.next {
    text-align: left;
  }

  .chapter-row {
    grid-template-columns: 34px minmax(0, 1fr);
  }

  .row-range {
    display: none;
  }

  .search-head {
    padding: 16px;
  }

  .search-field {
    padding: 16px;
  }

  .search-results {
    padding: 0 16px 16px;
  }

}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .sidebar {
    transition: none;
  }
}

@media print {
  body {
    background: #ffffff;
    color: #000000;
    font-size: 11pt;
  }

  .topbar,
  .sidebar,
  .page-rail,
  .sidebar-backdrop,
  .search-dialog,
  .page-turn,
  .primary-action {
    display: none !important;
  }

  .site-shell {
    display: block;
  }

  .main-content {
    max-width: none;
    padding: 0;
  }

  .page-header,
  .doc-section + .doc-section,
  .definition-block,
  .chapter-section,
  .principles {
    border-color: #b6b6b6;
  }

  .doc-section,
  .doc-section h2,
  .doc-section h3 {
    break-after: avoid-page;
  }

  .doc-section p,
  .doc-section li,
  pre,
  blockquote {
    break-inside: avoid;
  }

}