:root {
  --color-surface: #f8f8f8;
  --color-surface-alt: #efefef;
  --color-surface-deep: #e2e3e3;
  --color-ink: #42484d;
  --color-ink-soft: #676e74;
  --color-ink-muted: #798086;
  --color-line: #d7d8d9;
  --color-primary: #3a79b0;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dde6ee;
  --color-accent: #d83822;
  --color-accent-ink: #ffffff;
  --color-highlight: #f2d5d1;
  --color-focus: #d62c15;
  --color-contrast-surface: #0f1317;
  --color-contrast-ink: #e4e6e7;
  --color-contrast-line: #3e4145;
  --color-contrast-accent: #df4935;
  --overlay-scrim: linear-gradient(180deg, rgba(15, 19, 23, 0.35) 0%, rgba(15, 19, 23, 0.72) 55%, rgba(15, 19, 23, 0.92) 100%);
  --font-heading: ui-monospace, SFMono-Regular, Menlo, Consolas, "PingFang SC", monospace;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 12.9px;
  --text-sm: 15.5px;
  --text-base: 17px;
  --text-lg: 20.4px;
  --text-xl: 24.5px;
  --text-2xl: 29.4px;
  --text-3xl: 35.3px;
  --text-4xl: 42.3px;
  --text-display: clamp(34px, 4.7vw, 60px);
  --text-figure: clamp(28px, 3.4vw, 43px);
  --weight-heading: 625;
  --weight-body: 400;
  --leading-body: 1.77;
  --leading-heading: 1.21;
  --tracking-heading: 0.004em;
  --radius-sm: 1px;
  --radius-md: 2px;
  --radius-lg: 4px;
  --radius-pill: 4px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1180px;
  --measure: 77ch;
  --gutter: 32px;
  --section-y: 76px;
  --section-y-lg: 106px;
}

*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: 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;
}

img { display: block; max-width: 100%; height: auto; }

[hidden] { display: none !important; }

[id] { scroll-margin-top: var(--space-8); }

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 120ms linear;
}

a:hover { color: color-mix(in srgb, var(--color-primary) 74%, var(--color-ink)); }

p a,
li a,
.t-link,
.crumbs a,
.footer-list a {
  background-image: linear-gradient(currentColor, currentColor);
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0% var(--border-thin);
  transition: background-size 120ms linear, color 120ms linear;
}

p a:hover,
li a:hover,
.t-link:hover,
.crumbs a:hover,
.footer-list a:hover { background-size: 100% var(--border-thin); }

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

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-2);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }

h2, h3 {
  border-left: 3px solid var(--color-primary);
  padding-left: var(--space-2);
}

p { margin: 0 0 var(--space-2); }
ul, ol { margin: 0 0 var(--space-2); padding-left: var(--space-3); }
li { margin-bottom: 4px; }
li:last-child { margin-bottom: 0; }

strong { font-weight: var(--weight-heading); }

code, kbd, samp {
  font-family: var(--font-mono);
  font-size: 0.94em;
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 1px 5px;
}

hr {
  border: 0;
  border-top: var(--border-thin) solid var(--color-line);
  margin: var(--space-3) 0;
}

.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.05;
  letter-spacing: -0.012em;
  color: var(--color-ink);
}

.eyebrow {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-1);
}

.lede {
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.measure { max-width: var(--measure); }

.num,
.data-figure,
.kpi__value,
.readout-num,
.nav-meta,
.rail-index {
  font-variant-numeric: tabular-nums;
}

.callout {
  border-left: 3px solid var(--color-primary);
  padding: 2px 0 2px var(--space-2);
  margin: var(--space-3) 0;
  color: var(--color-ink);
}

.callout--alert { border-left-color: var(--color-accent); }
.callout--alert strong { color: var(--color-accent); }

.tag {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  background: var(--color-surface);
}

.tag--accent {
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.crumbs {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  margin-bottom: var(--space-3);
}

.crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.crumbs li { list-style: none; margin: 0; }
.crumbs li + li::before { content: "/"; margin-right: 6px; color: var(--color-line); }
.crumbs a { color: var(--color-ink-muted); }
.crumbs a:hover { color: var(--color-primary); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  line-height: 1;
  padding: 12px 18px;
  background: transparent;
  color: var(--color-ink);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color 120ms linear, color 120ms linear, border-color 120ms linear;
}

.btn:hover {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
}

.btn--primary {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background: color-mix(in srgb, var(--color-primary) 82%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
  border-color: color-mix(in srgb, var(--color-primary) 82%, var(--color-contrast-surface));
}

.btn[data-copied] {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background: var(--color-highlight);
}

/* ---------- 布局容器与栅格 ---------- */
.wrap {
  width: 100%;
  max-width: calc(var(--container) + var(--space-8));
  margin-inline: auto;
  padding-inline: var(--space-4);
}

main { display: block; }

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-6); }

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

.grid-12 > * { grid-column: 1 / -1; }
.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-9 { grid-column: span 9; }
.span-12 { grid-column: 1 / -1; }

/* ---------- 头部 ---------- */
.site-header {
  position: relative;
  z-index: 30;
  background: var(--color-surface);
}

.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 60;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  padding: var(--space-1) var(--space-2);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
  transition: top 120ms linear;
}

.skip-link:focus { top: var(--space-2); color: var(--color-contrast-ink); }

.masthead { padding-block: var(--space-3) 0; }

.masthead-lockup {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: center;
  gap: var(--space-1) var(--space-3);
  text-align: center;
}

.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: 0.08em;
  color: var(--color-ink);
  background: none;
}

.brand-name:hover { color: var(--color-primary); }

.brand-note {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.02em;
  line-height: 1.6;
}

.masthead-rule {
  position: relative;
  height: var(--border-thin);
  background: var(--color-line);
  margin-top: var(--space-3);
}

.masthead-rule::before,
.masthead-rule::after {
  content: "";
  position: absolute;
  top: -3px;
  width: var(--border-thin);
  height: 7px;
  background: var(--color-ink-muted);
}

.masthead-rule::before { left: 0; }
.masthead-rule::after { right: 0; }

.nav-row {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding-block: var(--space-1);
}

.nav {
  flex: 1 1 auto;
  min-width: 0;
  display: flex;
  justify-content: center;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: var(--space-1) var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-item { margin: 0; list-style: none; }

.nav-link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  background: none;
  transition: color 120ms linear, border-color 120ms linear;
}

.nav-link:hover { color: var(--color-ink); background: none; }

.nav-link[aria-current="page"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.nav-meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.nav-link[aria-current="page"] .nav-meta { color: var(--color-primary); }

.header-readout {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  white-space: nowrap;
}

.readout-num {
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  color: var(--color-primary);
}

.readout-sep { color: var(--color-line); }
.readout-text { color: var(--color-ink-muted); }

.rail-toggle {
  flex: 0 0 auto;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
  background: transparent;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  cursor: pointer;
  transition: color 120ms linear, border-color 120ms linear, background-color 120ms linear;
}

.rail-toggle:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
  background: transparent;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  cursor: pointer;
}

.nav-toggle-icon {
  position: relative;
  display: inline-block;
  width: 14px;
  height: 8px;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 14px;
  height: var(--border-thin);
  background: currentColor;
  transition: transform 120ms linear;
}

.nav-toggle-icon::before { top: 0; }
.nav-toggle-icon::after { bottom: 0; }

.nav-toggle[data-open] .nav-toggle-icon::before { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[data-open] .nav-toggle-icon::after { transform: translateY(-3.5px) rotate(-45deg); }

/* ---------- 文档骨架：左轨 + 正文 ---------- */
.doc-layout {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
}

.doc-main {
  flex: 1 1 auto;
  min-width: 0;
}

.toc-rail {
  position: sticky;
  top: var(--space-4);
  flex: 0 0 216px;
  width: 216px;
  align-self: flex-start;
  padding-right: var(--space-3);
  border-right: var(--border-thin) solid var(--color-line);
}

.toc-rail[data-collapsed] { display: none; }

.toc-rail-title {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-2);
}

.toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc-list li {
  margin: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

.toc-list li:last-child { border-bottom: var(--border-thin) solid var(--color-line); }

.rail-link {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  padding: 7px 0 7px var(--space-2);
  border-left: 3px solid transparent;
  background: none;
  transition: color 120ms linear, border-color 180ms linear, background-color 120ms linear;
}

.rail-link:hover { color: var(--color-ink); background: var(--color-surface-alt); }

.rail-link[aria-current="true"] {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  background: var(--color-primary-soft);
}

.rail-index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* ---------- 数据面板与表格 ---------- */
.data-panel {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}

.data-panel a { color: var(--color-contrast-ink); }
.data-panel a:hover { color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-primary)); }

.data-line {
  height: var(--border-thin);
  background: var(--color-contrast-line);
  margin: var(--space-2) 0;
  transition: background-color 160ms linear;
}

.data-panel:hover .data-line { background: color-mix(in srgb, var(--color-contrast-line) 55%, var(--color-contrast-ink)); }

.data-figure {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1.05;
  color: var(--color-contrast-ink);
}

.data-figure.is-alert { color: var(--color-contrast-accent); }

.data-kpi {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, var(--color-contrast-surface));
}

.data-panel .callout { border-left-color: var(--color-contrast-accent); color: var(--color-contrast-ink); }

.kpi {
  border-top: var(--border-thin) solid var(--color-line);
  padding-top: var(--space-1);
}

.kpi__value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1.05;
  color: var(--color-ink);
}

.kpi__label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  margin-top: 4px;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.data-table caption {
  caption-side: top;
  text-align: left;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  padding-bottom: var(--space-1);
}

.data-table th {
  background: var(--color-surface-deep);
  color: var(--color-ink-soft);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: var(--weight-heading);
  text-align: left;
  letter-spacing: 0.04em;
  padding: 10px 14px;
  border-bottom: var(--border-thin) solid var(--color-line);
}

.data-table td {
  padding: 10px 14px;
  color: var(--color-ink);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.data-table tbody tr:nth-child(even) { background: var(--color-surface-alt); }
.data-table tbody tr { transition: background-color 120ms linear; }
.data-table tbody tr:hover { background: var(--color-primary-soft); }

.data-table tbody td:first-child { position: relative; }

.data-table tbody tr:hover td:first-child::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 50%;
  width: 4px;
  height: 4px;
  margin-top: -2px;
  background: var(--color-primary);
}

/* ---------- 交互组件 ---------- */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-3);
}

.tab {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  padding: var(--space-1) 2px;
  cursor: pointer;
  transition: color 120ms linear, border-color 120ms linear;
}

.tab:hover { color: var(--color-ink); }

.tab[aria-selected="true"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.tab-panel { display: none; }
.tab-panel[data-active] { display: block; }

.chip {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
  background: transparent;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  padding: 6px 12px;
  cursor: pointer;
  transition: color 120ms linear, background-color 120ms linear, border-color 120ms linear;
}

.chip:hover { color: var(--color-primary); border-color: var(--color-primary); }

.chip[aria-pressed="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.disclosure {
  border-top: var(--border-thin) solid var(--color-line);
}

.disclosure:last-of-type { border-bottom: var(--border-thin) solid var(--color-line); }

.disclosure summary {
  position: relative;
  list-style: none;
  cursor: pointer;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink);
  padding: 12px 0 12px 22px;
}

.disclosure summary::-webkit-details-marker { display: none; }

.disclosure summary::before {
  content: "+";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  color: var(--color-primary);
}

.disclosure[open] summary::before { content: "–"; }

.disclosure-body {
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  padding: 0 0 var(--space-2) 22px;
}

/* ---------- 媒体容器（展签式） ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  background: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.06);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.media-frame--plain::after { display: none; }

.media-frame > figcaption,
.media-tag {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  max-width: 88%;
  background: var(--color-surface);
  border-top: var(--border-thin) solid var(--color-line);
  border-right: var(--border-thin) solid var(--color-line);
  padding: 6px 12px;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  line-height: 1.5;
  color: var(--color-ink-soft);
}

.media-tag-num {
  display: block;
  font-family: var(--font-mono);
  color: var(--color-primary);
}

/* ---------- 页脚 ---------- */
.site-footer {
  margin-top: var(--section-y-lg);
  background: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-top { padding-block: var(--space-6) var(--space-4); }

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-3);
  padding-bottom: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-4);
}

.footer-brand .brand-name { font-size: var(--text-lg); }

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
}

.footer-col { min-width: 0; }

.footer-col-title {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0 0 var(--space-2);
  padding-left: 0;
  border-left: 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.08em;
  color: var(--color-ink);
}

.footer-col-title::before {
  content: "";
  flex: 0 0 auto;
  width: 3px;
  height: 12px;
  background: var(--color-primary);
}

.footer-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.footer-list li {
  position: relative;
  margin: 0;
  padding-left: 14px;
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.footer-list li::before {
  content: "–";
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  color: var(--color-ink-muted);
}

.footer-list a { color: var(--color-ink-soft); }
.footer-list a:hover { color: var(--color-primary); }
.footer-list .is-current { color: var(--color-primary); font-weight: var(--weight-heading); }

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3) var(--space-4);
  border-top: var(--border-thin) solid var(--color-line);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.footer-legal-item { margin: 0; }

/* ---------- 响应式 ---------- */
@media (max-width: 1100px) {
  .nav-list { gap: var(--space-1) var(--space-3); }
  .header-readout { font-size: var(--text-xs); }
}

@media (max-width: 960px) {
  .doc-layout { display: block; }

  .toc-rail {
    position: static;
    top: auto;
    width: auto;
    flex: 1 1 auto;
    padding-right: 0;
    padding-bottom: var(--space-2);
    border-right: 0;
    border-bottom: var(--border-thin) solid var(--color-line);
    margin-bottom: var(--space-3);
  }

  .toc-list {
    display: flex;
    gap: var(--space-2);
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .toc-list li { border-top: 0; border-bottom: 0; }

  .rail-link {
    white-space: nowrap;
    border-left: 0;
    border-bottom: 2px solid transparent;
    padding: 6px 2px;
  }

  .rail-link[aria-current="true"] {
    border-left-color: transparent;
    border-bottom-color: var(--color-primary);
    background: transparent;
  }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .grid-12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .span-3, .span-4, .span-5, .span-6 { grid-column: span 3; }
  .span-7, .span-8, .span-9 { grid-column: span 6; }
}

@media (max-width: 880px) {
  .nav-row { flex-wrap: nowrap; }

  .rail-toggle { order: 1; }

  .nav {
    order: 2;
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 40;
    background: var(--color-surface);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thin) solid var(--color-line);
    padding: var(--space-1) var(--space-4) var(--space-2);
  }

  .nav[data-open] { display: block; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: 100%;
  }

  .nav-item { border-bottom: var(--border-thin) solid var(--color-line); }
  .nav-item:last-child { border-bottom: 0; }

  .nav-link {
    justify-content: space-between;
    width: 100%;
    font-size: var(--text-base);
    padding: var(--space-2) 0;
    border-bottom: 2px solid transparent;
  }

  .nav-link[aria-current="page"] { border-bottom-color: transparent; background: var(--color-primary-soft); padding-inline: var(--space-1); }

  .header-readout { display: none; }
  .nav-toggle { display: inline-flex; order: 3; }
}

@media (max-width: 640px) {
  .wrap { padding-inline: var(--space-3); }

  .masthead-lockup { flex-direction: column; align-items: center; gap: var(--space-1); }
  .brand-name { font-size: var(--text-lg); }

  .footer-grid { grid-template-columns: 1fr; gap: var(--space-3); }

  .grid-12 { grid-template-columns: 1fr; }
  .span-3, .span-4, .span-5, .span-6, .span-7, .span-8, .span-9, .span-12 { grid-column: 1 / -1; }

  .footer-legal { flex-direction: column; align-items: flex-start; }

  .data-table th, .data-table td { padding: 8px 10px; }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0ms !important;
    animation-duration: 0ms !important;
    animation-iteration-count: 1 !important;
  }
}