:root {
  --color-surface: #f2f1f0;
  --color-surface-alt: #eae8e7;
  --color-surface-deep: #dedcda;
  --color-ink: #49433b;
  --color-ink-soft: #70665c;
  --color-ink-muted: #8b8074;
  --color-line: #d4d2cf;
  --color-primary: #a46623;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e7ded3;
  --color-accent: #d83a22;
  --color-accent-ink: #ffffff;
  --color-highlight: #edd0cb;
  --color-focus: #cd2c13;
  --color-contrast-surface: #292016;
  --color-contrast-ink: #e7e6e4;
  --color-contrast-line: #534c43;
  --color-contrast-accent: #e35e4a;
  --overlay-scrim: linear-gradient(180deg, rgba(41, 32, 22, 0.35) 0%, rgba(41, 32, 22, 0.72) 55%, rgba(41, 32, 22, 0.92) 100%);
  --font-heading: "Songti SC", "Source Han Serif SC", "Noto Serif SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 13.7px;
  --text-sm: 16.4px;
  --text-base: 18px;
  --text-lg: 21.6px;
  --text-xl: 25.9px;
  --text-2xl: 31.1px;
  --text-3xl: 37.3px;
  --text-4xl: 44.8px;
  --text-display: clamp(38px, 7.7vw, 99px);
  --text-figure: clamp(31px, 5.5vw, 71px);
  --weight-heading: 660;
  --weight-body: 400;
  --leading-body: 1.87;
  --leading-heading: 1.19;
  --tracking-heading: -0.001em;
  --radius-sm: 10px;
  --radius-md: 12px;
  --radius-lg: 15px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(73, 67, 59, 0.08);
  --shadow-2: 0 18px 44px rgba(73, 67, 59, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1080px;
  --measure: 73ch;
  --gutter: 16px;
  --section-y: 94px;
  --section-y-lg: 132px;
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body, h1, h2, h3, h4, p, figure, blockquote, dl, dd, ul, ol { margin: 0; }
ul, ol { padding: 0; list-style: none; }
body {
  background-color: 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);
  letter-spacing: 0.005em;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
  background-image:
    repeating-linear-gradient(0deg, rgba(73, 67, 59, 0.026) 0 1px, transparent 1px 4px),
    repeating-linear-gradient(90deg, rgba(73, 67, 59, 0.02) 0 1px, transparent 1px 6px);
}
.site-header, .site-footer, main, .shell { position: relative; z-index: 1; }
img, svg, video { max-width: 100%; display: block; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* ---------- 中文排版 ---------- */
h1, h2, h3, h4, .h1, .h2, .h3 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}
.h1 { font-size: var(--text-4xl); }
.h2 { font-size: var(--text-3xl); }
.h3 { font-size: var(--text-xl); }
h1 + p, h2 + p, h3 + p { margin-top: var(--space-3); }
p { max-width: var(--measure); }
.prose { max-width: var(--measure); }
.prose > * + * { margin-top: var(--space-3); }
.prose p, .prose li { color: var(--color-ink); }
.prose ul, .prose ol { display: grid; gap: var(--space-2); padding-left: 0; }
.prose li { padding-left: var(--space-3); position: relative; }
.prose li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.72em;
  width: 10px; height: 2px;
  background-color: var(--color-primary);
}
.display {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--color-ink);
}
.figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}
.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; letter-spacing: -0.01em; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.eyebrow::before {
  content: "";
  width: 24px; height: 1px;
  background-color: var(--color-accent);
}
.lede { font-size: var(--text-lg); color: var(--color-ink-soft); max-width: var(--measure); }
.chapter-num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 600;
  line-height: 1;
  color: var(--color-primary);
  display: block;
  letter-spacing: -0.03em;
}
.meta {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.06em;
}

/* ---------- 布局 ---------- */
.shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}
main { display: block; }
.section { padding-block: var(--section-y); }
.section--tight { padding-block: calc(var(--section-y) * 0.6); }
.section--lg { padding-block: var(--section-y-lg); }
.section--alt { background-color: var(--color-surface-alt); }
.section--deep {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--deep h1, .section--deep h2, .section--deep h3, .section--deep h4,
.section--deep .h1, .section--deep .h2, .section--deep .h3 { color: var(--color-contrast-ink); }
.section--deep p, .section--deep li, .section--deep .prose p { color: var(--color-contrast-ink); }
.section--deep .lede { color: color-mix(in srgb, var(--color-contrast-ink) 80%, var(--color-contrast-surface)); }
.section--deep .eyebrow { color: var(--color-contrast-accent); }
.section--deep .meta { color: color-mix(in srgb, var(--color-contrast-ink) 65%, var(--color-contrast-surface)); }
.section--deep .figure { color: var(--color-contrast-accent); }
.section--deep .chapter-num { color: var(--color-contrast-accent); }
.section--deep .rule { background-color: var(--color-contrast-line); }
.section--warm { background-color: var(--color-primary-soft); }
.section--warm h1, .section--warm h2, .section--warm h3 { color: var(--color-ink); }

.grid { display: grid; gap: var(--space-3); grid-template-columns: repeat(12, minmax(0, 1fr)); }
.col-3 { grid-column: span 3; }
.col-4 { grid-column: span 4; }
.col-5 { grid-column: span 5; }
.col-6 { grid-column: span 6; }
.col-7 { grid-column: span 7; }
.col-8 { grid-column: span 8; }
.col-9 { grid-column: span 9; }
.col-12 { grid-column: span 12; }
.stack { display: grid; gap: var(--space-3); }
.stack--sm { gap: var(--space-2); }
.stack--lg { gap: var(--space-6); }
.rule { height: 1px; background-color: var(--color-line); border: 0; }
.rule--inset { margin-inline: auto; max-width: var(--container); opacity: 0.9; }

/* ---------- 框体与卡片 ---------- */
.panel {
  background-color: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: var(--shadow-1);
}
.panel--warm {
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 26%, transparent);
}
.panel--deep {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.panel--deep h1, .panel--deep h2, .panel--deep h3 { color: var(--color-contrast-ink); }
.panel--deep p { color: var(--color-contrast-ink); }
.panel--flat { box-shadow: none; }
.panel--accent-edge { border-left: 3px solid var(--color-accent); }

/* ---------- 按钮与链接 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 13px 26px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: background-color 220ms ease, border-color 220ms ease, color 220ms ease, box-shadow 220ms ease, transform 220ms ease;
}
.btn:hover { border-color: var(--color-primary); color: var(--color-primary); transform: translateY(-1px); box-shadow: var(--shadow-1); }
.btn--primary { background-color: var(--color-primary); border-color: var(--color-primary); color: var(--color-primary-ink); }
.btn--primary:hover { background-color: color-mix(in srgb, var(--color-primary) 86%, var(--color-contrast-surface)); color: var(--color-primary-ink); }
.btn--accent { background-color: var(--color-accent); border-color: var(--color-accent); color: var(--color-accent-ink); }
.btn--accent:hover { background-color: color-mix(in srgb, var(--color-accent) 86%, var(--color-contrast-surface)); color: var(--color-accent-ink); }
.btn--ghost { background-color: transparent; }
.btn--ghost:hover { background-color: var(--color-highlight); border-color: var(--color-accent); color: var(--color-accent); }
.cta-row { display: flex; flex-wrap: wrap; gap: var(--space-2); align-items: center; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-accent);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: border-color 200ms ease, gap 200ms ease, color 200ms ease;
}
.link-arrow::after { content: "→"; font-family: var(--font-mono); }
.link-arrow:hover { border-color: var(--color-accent); gap: var(--space-2); }
.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) dashed var(--color-line);
  font-size: var(--text-xs);
  font-family: var(--font-mono);
  color: var(--color-ink-soft);
  background-color: transparent;
  transition: border-color 200ms ease, color 200ms ease, background-color 200ms ease;
}
.copy-btn:hover { border-color: var(--color-primary); color: var(--color-primary); background-color: var(--color-primary-soft); }
.copy-btn[data-copied="true"] { border-style: solid; border-color: var(--color-accent); color: var(--color-accent); }

.tag-list { display: flex; flex-wrap: wrap; gap: var(--space-1); }
.tag {
  display: inline-flex;
  align-items: center;
  padding: 5px 14px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
  letter-spacing: 0.04em;
}
.tag[aria-pressed="true"], .tag.is-active {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ---------- 图片容器 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-deep);
  box-shadow: var(--shadow-1);
  aspect-ratio: 16 / 10;
  transition: box-shadow 260ms ease, border-color 260ms ease;
}
.media--wide { aspect-ratio: 21 / 9; }
.media--square { aspect-ratio: 1 / 1; }
.media--tall { aspect-ratio: 3 / 4; }
.media-img { width: 100%; height: 100%; object-fit: cover; display: block; }
.media:hover { box-shadow: var(--shadow-2); border-color: color-mix(in srgb, var(--color-primary) 40%, var(--color-line)); }
.media-scrim {
  position: absolute;
  inset: 0;
  background-image: var(--overlay-scrim);
  pointer-events: none;
}
.media-caption {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 2;
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  margin: 0;
}
.media-caption .mono { color: var(--color-contrast-accent); }
.media-badge {
  position: absolute;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 2;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
}

/* ---------- 状态面板与表格 ---------- */
.status-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-2);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-contrast-line);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.status-item {
  flex: 1 1 160px;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-contrast-line);
}
.status-label { display: block; font-size: var(--text-xs); letter-spacing: 0.1em; color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface)); }
.status-value { display: block; font-family: var(--font-mono); font-size: var(--text-xl); color: var(--color-contrast-accent); margin-top: 4px; }

.stepper { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.step {
  flex: 1 1 180px;
  padding: var(--space-3);
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  transition: border-color 220ms ease, background-color 220ms ease, color 220ms ease;
}
.step[aria-current="step"] {
  border-color: var(--color-accent);
  background-color: var(--color-highlight);
  color: var(--color-ink);
}
.step-index { display: block; font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-ink-muted); margin-bottom: 4px; }
.step[aria-current="step"] .step-index { color: var(--color-accent); }

.table-wrap {
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface);
  box-shadow: var(--shadow-1);
}
.spec-table { min-width: 640px; font-size: var(--text-sm); }
.spec-table caption { text-align: left; padding: var(--space-3) var(--space-3) 0; color: var(--color-ink-muted); font-size: var(--text-xs); }
.spec-table th, .spec-table td { padding: var(--space-2) var(--space-3); text-align: left; border-bottom: var(--border-thin) solid var(--color-line); }
.spec-table thead th {
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
}
.spec-table tbody tr { transition: background-color 180ms ease; }
.spec-table tbody tr:hover { background-color: var(--color-highlight); }
.spec-table tbody tr:last-child th, .spec-table tbody tr:last-child td { border-bottom: 0; }
.spec-table .num { font-family: var(--font-mono); color: var(--color-primary); }
.row-note { display: block; max-height: 0; overflow: hidden; font-size: var(--text-xs); color: var(--color-ink-muted); transition: max-height 240ms ease; }
.spec-table tbody tr:hover .row-note, .spec-table tbody tr:focus-within .row-note { max-height: 4em; }

/* ---------- 目录 ---------- */
.toc {
  position: sticky;
  top: var(--space-6);
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
}
.toc-title { font-family: var(--font-mono); font-size: var(--text-xs); letter-spacing: 0.14em; color: var(--color-ink-muted); margin-bottom: var(--space-2); }
.toc-link {
  display: block;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  border-left: 2px solid transparent;
  transition: color 180ms ease, border-color 180ms ease, background-color 180ms ease;
}
.toc-link:hover { color: var(--color-ink); background-color: var(--color-highlight); }
.toc-link.is-active { color: var(--color-accent); border-left-color: var(--color-accent); background-color: var(--color-highlight); }

/* ---------- 显现 ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 520ms ease, transform 520ms ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- 页头 ---------- */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 60;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-size: var(--text-sm);
  transition: top 200ms ease;
}
.skip-link:focus { top: var(--space-2); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: color-mix(in srgb, var(--color-surface) 92%, transparent);
  backdrop-filter: blur(6px);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.header-utility {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-xs);
}
.header-utility-inner {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-height: 36px;
  flex-wrap: wrap;
}
.utility-place { font-family: var(--font-mono); color: var(--color-contrast-accent); letter-spacing: 0.08em; }
.utility-sep { width: 1px; height: 12px; background-color: var(--color-contrast-line); }
.utility-icp { font-family: var(--font-mono); color: color-mix(in srgb, var(--color-contrast-ink) 82%, var(--color-contrast-surface)); }
.utility-note { margin-left: auto; color: color-mix(in srgb, var(--color-contrast-ink) 68%, var(--color-contrast-surface)); }

.header-bar { background-color: transparent; }
.header-bar-inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-height: 72px;
}
.brand { display: inline-flex; flex-direction: column; gap: 2px; }
.brand-mark {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  color: var(--color-primary);
}
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  letter-spacing: 0.06em;
}
.site-nav { margin-left: auto; }
.nav-list { display: flex; align-items: center; gap: var(--space-3); }
.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 2px;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  transition: color 200ms ease;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1px;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 240ms ease;
}
.nav-link:hover { color: var(--color-ink); }
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: var(--color-accent); font-weight: 600; }
.nav-link[aria-current="page"]::after { transform: scaleX(1); }
.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 9px 22px;
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.06em;
  transition: background-color 220ms ease, transform 220ms ease, box-shadow 220ms ease;
}
.nav-cta:hover { background-color: var(--color-accent); transform: translateY(-1px); box-shadow: var(--shadow-1); }
.nav-toggle { display: none; }

.nav-toggle {
  align-items: center;
  gap: var(--space-1);
  padding: 10px 16px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  background-color: var(--color-surface);
}
.nav-toggle-bars {
  position: relative;
  width: 16px; height: 1px;
  background-color: currentColor;
  display: block;
}
.nav-toggle-bars::before, .nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px; height: 1px;
  background-color: currentColor;
}
.nav-toggle-bars::before { top: -5px; }
.nav-toggle-bars::after { top: 5px; }
.nav-toggle[aria-expanded="true"] { border-color: var(--color-accent); color: var(--color-accent); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars { background-color: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before { transform: rotate(45deg); top: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { transform: rotate(-45deg); top: 0; }

.scroll-progress {
  position: absolute;
  left: 0; bottom: -1px;
  height: 2px;
  width: 0;
  background-color: var(--color-accent);
  transition: width 120ms linear;
}

/* ---------- 页脚 ---------- */
.site-footer {
  background-color: var(--color-surface-deep);
  color: var(--color-ink);
  border-top: var(--border-thin) solid var(--color-line);
  padding-block: var(--space-8);
  margin-top: var(--section-y);
}
.footer-inner { display: grid; gap: var(--space-6); }
.footer-top { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: var(--space-6); }
.footer-brand { display: grid; gap: var(--space-2); }
.footer-mark { font-family: var(--font-mono); font-size: var(--text-xs); letter-spacing: 0.24em; color: var(--color-primary); }
.footer-name { font-family: var(--font-heading); font-size: var(--text-xl); font-weight: var(--weight-heading); letter-spacing: 0.06em; }
.footer-note { font-size: var(--text-sm); color: var(--color-ink-muted); max-width: 42ch; }
.footer-nav .footer-list { display: grid; gap: var(--space-1); }
.footer-list a {
  display: inline-block;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  border-bottom: 1px solid transparent;
  transition: color 200ms ease, border-color 200ms ease;
}
.footer-list a:hover { color: var(--color-primary); border-color: var(--color-primary); }
.footer-contact { display: grid; gap: var(--space-1); align-content: start; }
.footer-label { font-family: var(--font-mono); font-size: var(--text-xs); letter-spacing: 0.14em; color: var(--color-ink-muted); margin-bottom: var(--space-1); }
.footer-line { font-size: var(--text-sm); color: var(--color-ink-soft); }
.footer-line a { border-bottom: 1px solid var(--color-line); transition: color 200ms ease, border-color 200ms ease; }
.footer-line a:hover { color: var(--color-accent); border-color: var(--color-accent); }
.footer-line--soft { color: var(--color-ink-muted); }
.footer-bottom { display: flex; flex-wrap: wrap; gap: var(--space-2); align-items: center; justify-content: space-between; }
.footer-legal, .footer-meta { display: flex; flex-wrap: wrap; gap: var(--space-1); font-size: var(--text-xs); color: var(--color-ink-muted); }
.footer-legal a { border-bottom: 1px solid transparent; transition: color 200ms ease, border-color 200ms ease; }
.footer-legal a:hover { color: var(--color-accent); border-color: var(--color-accent); }

/* ---------- 平板 ---------- */
@media (max-width: 980px) {
  :root { --section-y: 72px; --section-y-lg: 96px; }
  .col-4, .col-5, .col-6, .col-7, .col-8, .col-9 { grid-column: span 12; }
  .col-3 { grid-column: span 6; }
  .footer-top { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: span 2; }
}

/* ---------- 移动 ---------- */
@media (max-width: 720px) {
  body { font-size: var(--text-sm); }
  .header-bar-inner { min-height: 64px; flex-wrap: wrap; }
  .nav-toggle { display: inline-flex; margin-left: auto; }
  .site-nav {
    flex-basis: 100%;
    margin-left: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 280ms ease;
  }
  .site-nav[data-open] { max-height: 520px; }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; padding-block: var(--space-2); }
  .nav-list li { border-bottom: var(--border-thin) solid var(--color-line); }
  .nav-list li:last-child { border-bottom: 0; }
  .nav-link { display: block; padding: 14px 4px; font-size: var(--text-base); }
  .nav-cta-item { border-bottom: 0 !important; padding-top: var(--space-2); }
  .nav-cta { width: 100%; justify-content: center; padding: 12px 22px; }
  .utility-note { display: none; }
  .footer-top { grid-template-columns: 1fr; gap: var(--space-4); }
  .footer-brand { grid-column: span 1; }
  .footer-bottom { flex-direction: column; align-items: flex-start; gap: var(--space-2); }
  .grid { gap: var(--space-2); }
  .panel { padding: var(--space-3); }
  .toc { position: static; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .reveal { opacity: 1; transform: none; }
  .scroll-progress { transition: none; }
}