:root {
  --color-surface: #f9f9f9;
  --color-surface-alt: #efefef;
  --color-surface-deep: #e1e1e2;
  --color-ink: #303236;
  --color-ink-soft: #5b6066;
  --color-ink-muted: #757980;
  --color-line: #d5d5d6;
  --color-primary: #0e6af1;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #d8e5f8;
  --color-accent: #488406;
  --color-accent-ink: #ffffff;
  --color-highlight: #d9e4cd;
  --color-focus: #438000;
  --color-contrast-surface: #101926;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #3f4650;
  --color-contrast-accent: #85f40b;
  --overlay-scrim: linear-gradient(180deg, rgba(16, 25, 38, 0.35) 0%, rgba(16, 25, 38, 0.72) 55%, rgba(16, 25, 38, 0.92) 100%);
  --font-heading: "Source Han Sans SC", "Noto Sans SC", SimHei, "Microsoft YaHei", sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 8.7px;
  --text-sm: 13.1px;
  --text-base: 16px;
  --text-lg: 24.0px;
  --text-xl: 36.0px;
  --text-2xl: 54.0px;
  --text-3xl: 81.0px;
  --text-4xl: 121.5px;
  --text-display: clamp(39px, 8.0vw, 103px);
  --text-figure: clamp(33px, 5.8vw, 74px);
  --weight-heading: 815;
  --weight-body: 400;
  --leading-body: 1.68;
  --leading-heading: 1.24;
  --tracking-heading: -0.011em;
  --radius-sm: 214px;
  --radius-md: 342px;
  --radius-lg: 469px;
  --radius-pill: 999px;
  --border-thin: 2px;
  --border-thick: 3px;
  --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: 1160px;
  --measure: 67ch;
  --gutter: 24px;
  --section-y: 85px;
  --section-y-lg: 119px;
}

/* ============ 1. Reset ============ */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  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);
  -webkit-font-smoothing: antialiased;
}

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

p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { padding: 0; border: 0; background: none; color: inherit; font: inherit; cursor: pointer; }
table { width: 100%; border-collapse: collapse; }
hr { height: 0; border: 0; }
[hidden] { display: none !important; }

:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 3px;
}

.site-footer :focus-visible,
.panel-dark :focus-visible,
.section--deep :focus-visible {
  outline-color: var(--color-contrast-accent);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: var(--space-3);
  top: var(--space-1);
  z-index: 90;
  padding: var(--space-2) var(--space-3);
  transform: translateY(-240%);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-accent);
  border: var(--border-thin) solid var(--color-contrast-accent);
  font-size: var(--text-sm);
  font-weight: 700;
  transition: transform 0.18s ease;
}

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

/* ============ 2. 布局骨架 ============ */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.section { padding: var(--section-y) 0; }
.section--lg { padding: var(--section-y-lg) 0; }
.section--tight { padding: var(--space-6) 0; }
.section--flush-top { padding-top: 0; }
.section--alt { background-color: var(--color-surface-alt); }
.section--primary { background-color: var(--color-primary-soft); }
.section--accent { background-color: var(--color-highlight); }

.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 { color: var(--color-contrast-ink); }
.section--deep .prose,
.section--deep .lede { color: var(--color-contrast-ink); }
.section--deep a:not(.btn) { color: var(--color-contrast-accent); }

.grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: var(--gutter);
}
.span-1 { grid-column: span 1; }
.span-2 { grid-column: span 2; }
.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }

.stack { display: flex; flex-direction: column; gap: var(--space-2); }
.stack--lg { gap: var(--space-4); }
.cluster { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-2); }

.rule {
  height: var(--border-thick);
  border: 0;
  background-color: var(--color-contrast-surface);
}
.rule--offset { width: min(72%, 640px); }
.rule--accent { background-color: var(--color-accent); }
.rule--thin { height: var(--border-thin); background-color: var(--color-line); }

.tick {
  display: inline-block;
  width: 14px;
  height: var(--border-thin);
  background-color: var(--color-accent);
  flex: 0 0 auto;
}

[id] { scroll-margin-top: 130px; }

/* ============ 3. 文字系统 ============ */
.kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}
.kicker::before {
  content: "";
  width: 26px;
  height: var(--border-thick);
  background-color: var(--color-accent);
}

.hero-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.02;
  letter-spacing: -0.02em;
}

.figure-value,
.chapter-num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1;
}

.title-xl { font-size: var(--text-xl); }
.title-lg { font-size: var(--text-lg); }
.title-md { font-size: var(--text-base); font-weight: 700; letter-spacing: 0.02em; }

.lede {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-ink-soft);
}

.meta {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-ink-muted);
}

.num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

.prose {
  max-width: var(--measure);
  color: var(--color-ink);
}
.prose p { margin-bottom: var(--space-3); }
.prose h2 { margin: var(--space-6) 0 var(--space-2); font-size: var(--text-xl); }
.prose h3 { margin: var(--space-4) 0 var(--space-2); font-size: var(--text-lg); }
.prose ul { margin: 0 0 var(--space-3); }
.prose li {
  position: relative;
  padding-left: var(--space-3);
  margin-bottom: var(--space-1);
}
.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 10px;
  height: var(--border-thin);
  background-color: var(--color-accent);
}
.prose strong { font-weight: 700; color: var(--color-ink); }

/* ============ 4. 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border: var(--border-thin) solid var(--color-ink);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.02em;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}
.btn:hover { transform: translate(-3px, -3px); }
.btn--primary {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn--accent {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--dark {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.btn--ghost {
  background-color: transparent;
  color: var(--color-ink);
  border-color: var(--color-ink);
}
.site-footer .btn--ghost,
.panel-dark .btn--ghost {
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
}
.site-footer .btn--ghost:hover,
.panel-dark .btn--ghost:hover {
  color: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
}

/* ============ 5. 面包屑 ============ */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}
.breadcrumb a { color: var(--color-ink-muted); }
.breadcrumb a:hover { color: var(--color-primary); }
.breadcrumb li + li::before {
  content: "/";
  margin-right: var(--space-1);
  color: var(--color-line);
}
.breadcrumb [aria-current="page"] { color: var(--color-ink); font-weight: 700; }

/* ============ 6. 基础组件 ============ */
.card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-3);
  background-color: var(--color-surface);
  border: var(--border-thick) solid var(--color-ink);
  transition: transform 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}
.card:hover { transform: translate(-4px, -4px); border-color: var(--color-primary); }
.card--blue { background-color: var(--color-primary-soft); border-color: var(--color-primary); }
.card--green { background-color: var(--color-highlight); border-color: var(--color-accent); }
.card--dark {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.card--dark:hover { border-color: var(--color-contrast-accent); }
.card-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
}
.card-title { font-size: var(--text-lg); }
.card-meta {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}
.card--dark .card-meta { color: var(--color-contrast-accent); }

.num-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 60px;
  height: 60px;
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
}
.num-badge--accent { background-color: var(--color-accent); color: var(--color-accent-ink); }
.num-badge--outline {
  background-color: transparent;
  color: var(--color-ink);
  border: var(--border-thick) solid var(--color-ink);
}

.chapter-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: clamp(78px, 13vw, 112px);
  height: clamp(78px, 13vw, 112px);
  border-radius: var(--radius-lg);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-ink-soft);
}
.tag--primary {
  background-color: var(--color-primary-soft);
  border-color: var(--color-primary);
  color: var(--color-ink);
}
.tag--accent {
  background-color: var(--color-highlight);
  border-color: var(--color-accent);
  color: var(--color-ink);
}

.panel-dark {
  padding: var(--space-4);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thick) solid var(--color-contrast-surface);
}
.panel-dark h2,
.panel-dark h3 { color: var(--color-contrast-ink); }
.panel-dark a { color: var(--color-contrast-accent); }
.panel-dark .meta { color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface)); }

.datum {
  padding-top: var(--space-2);
  border-top: var(--border-thick) solid var(--color-contrast-surface);
}
.datum-value {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: 1.1;
}
.datum-label {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.data-table { font-size: var(--text-sm); }
.data-table th,
.data-table td {
  padding: var(--space-2);
  text-align: left;
  border-bottom: var(--border-thin) solid var(--color-line);
  vertical-align: top;
}
.data-table thead th {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-mono);
  font-weight: 700;
  border-bottom-color: var(--color-contrast-line);
}
.data-table tbody tr:nth-child(even) { background-color: var(--color-surface-deep); }

.media {
  position: relative;
  display: block;
  padding: var(--space-1);
  background-color: var(--color-surface-alt);
  border: var(--border-thick) solid var(--color-ink);
}
.media > img,
.media > svg {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}
.media--tall > img,
.media--tall > svg { aspect-ratio: 4 / 5; }
.media--offset { margin-left: calc(-1 * var(--space-4)); }
.media-scrim {
  position: absolute;
  inset: var(--space-1);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}
.media-caption {
  padding-top: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.accordion { border-top: var(--border-thick) solid var(--color-contrast-surface); }
.accordion-item { border-bottom: var(--border-thin) solid var(--color-line); }
.accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  text-align: left;
}
.accordion-trigger:hover { color: var(--color-primary); }
.accordion-mark {
  position: relative;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
}
.accordion-mark::before,
.accordion-mark::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 10px;
  height: var(--border-thin);
  background-color: var(--color-primary-ink);
  transform: translate(-50%, -50%);
}
.accordion-mark::after { transform: translate(-50%, -50%) rotate(90deg); }
.accordion-trigger[aria-expanded="true"] .accordion-mark { background-color: var(--color-accent); }
.accordion-trigger[aria-expanded="true"] .accordion-mark::after { display: none; }
.accordion-panel {
  overflow: hidden;
  transition: max-height 0.28s ease;
}
.accordion-panel.is-init { transition: none; }
.accordion-content { padding: 0 0 var(--space-4); }

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
}
.filter-chip {
  padding: 6px 14px;
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface);
  font-size: var(--text-sm);
  font-weight: 700;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}
.filter-chip:hover { border-color: var(--color-primary); color: var(--color-primary); }
.filter-chip[aria-pressed="true"] {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.filter-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.side-index {
  position: sticky;
  top: 110px;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-left: var(--space-2);
  border-left: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
}
.side-index-link {
  padding: 6px 0;
  font-weight: 700;
  color: var(--color-ink-muted);
}
.side-index-link:hover { color: var(--color-primary); }
.side-index-link[aria-current="true"] { color: var(--color-ink); }
.side-index-link[aria-current="true"]::before {
  content: "";
  display: inline-block;
  width: 12px;
  height: var(--border-thin);
  margin-right: 8px;
  vertical-align: middle;
  background-color: var(--color-accent);
}

/* ============ 7. 头部 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: var(--color-surface);
  border-bottom: var(--border-thick) solid var(--color-ink);
}

.header-strip {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}
.header-strip-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-4);
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-1) var(--gutter);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
}
.strip-note {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  color: var(--color-contrast-ink);
}
.header-strip .tick { background-color: var(--color-contrast-accent); }
.strip-meta { color: color-mix(in srgb, var(--color-contrast-ink) 60%, var(--color-contrast-surface)); }

.header-frame {
  display: grid;
  grid-template-columns: minmax(0, 240px) 1fr auto;
  align-items: stretch;
  min-height: 78px;
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  padding: var(--space-2) var(--space-3) var(--space-2) 0;
}
.brand-mark {
  position: relative;
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
  overflow: hidden;
}
.brand-mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 50%;
  background-color: var(--color-accent);
}
.brand-text { display: flex; flex-direction: column; min-width: 0; }
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.1;
  letter-spacing: var(--tracking-heading);
}
.brand-note {
  overflow: hidden;
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  white-space: nowrap;
  text-overflow: ellipsis;
}

.site-nav { display: flex; align-items: stretch; min-width: 0; }
.nav-list { display: flex; align-items: stretch; flex-wrap: wrap; }
.nav-list > li { display: flex; }
.nav-link {
  display: flex;
  align-items: center;
  padding: 0 var(--space-3);
  border-left: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thick) solid transparent;
  font-size: var(--text-sm);
  font-weight: 700;
  white-space: nowrap;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}
.nav-link:hover { background-color: var(--color-primary-soft); }
.nav-link[aria-current="page"] {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  border-bottom-color: var(--color-accent);
}

.nav-slot { display: none; }
.nav-slot-link {
  display: block;
  padding: var(--space-2) 0;
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-primary);
}

.header-actions {
  display: flex;
  align-items: stretch;
  border-left: var(--border-thin) solid var(--color-line);
}
.action-link {
  display: flex;
  align-items: center;
  padding: 0 var(--space-3);
  font-size: var(--text-sm);
  font-weight: 700;
  white-space: nowrap;
  transition: background-color 0.2s ease, color 0.2s ease;
}
.action-link:hover { background-color: var(--color-primary-soft); }
.action-link--primary {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.action-link--primary:hover {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-accent);
}

.nav-toggle {
  position: relative;
  display: none;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  margin: auto 0 auto var(--space-2);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-pill);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.nav-toggle-bar {
  position: absolute;
  left: 50%;
  width: 20px;
  height: var(--border-thin);
  background-color: currentColor;
  transform: translateX(-50%);
  transition: transform 0.2s ease;
}
.nav-toggle-bar:nth-of-type(1) { top: 19px; }
.nav-toggle-bar:nth-of-type(2) { top: 29px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-of-type(1) {
  transform: translateX(-50%) translateY(5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-of-type(2) {
  transform: translateX(-50%) translateY(-5px) rotate(-45deg);
}

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: calc(-1 * var(--border-thick));
  height: var(--border-thick);
  overflow: hidden;
}
.scroll-progress > span {
  display: block;
  width: 100%;
  height: 100%;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
}

/* ============ 8. 页脚 ============ */
.site-footer {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thick) solid var(--color-accent);
}
.footer-ruler {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-1);
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-3) var(--gutter) 0;
}
.footer-ruler .tick {
  width: var(--border-thin);
  height: 10px;
  background-color: var(--color-contrast-line);
}
.footer-ruler .tick:nth-child(3n + 1) {
  height: 24px;
  background-color: var(--color-contrast-accent);
}
.footer-ruler .tick:nth-child(4n) { height: 16px; }

.footer-inner {
  display: grid;
  grid-template-columns: 1.25fr 1fr 1.15fr 1fr;
  gap: var(--space-4);
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-6) var(--gutter) var(--space-4);
}
.footer-brand { display: flex; flex-direction: column; gap: var(--space-2); align-items: flex-start; }
.footer-brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.1;
}
.footer-brand-note {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 66%, var(--color-contrast-surface));
}
.footer-col { display: flex; flex-direction: column; gap: var(--space-2); }
.footer-title {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-contrast-accent);
}
.footer-links { display: flex; flex-direction: column; gap: var(--space-1); }
.footer-links--sub {
  margin-top: var(--space-1);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}
.footer-links a {
  display: inline-block;
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  transition: color 0.2s ease;
}
.footer-links a:hover { color: var(--color-contrast-accent); }

.footer-contact { display: flex; flex-direction: column; gap: var(--space-2); }
.footer-contact li { display: flex; flex-direction: column; gap: 2px; }
.footer-label {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, var(--color-contrast-surface));
}
.footer-value { font-size: var(--text-base); }
.footer-hint {
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 70%, var(--color-contrast-surface));
}
.footer-cta { align-self: flex-start; }
.footer-note {
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-contrast-surface));
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-3) var(--gutter) var(--space-4);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
}
.footer-copy { color: var(--color-contrast-ink); }
.footer-meta { color: var(--color-contrast-accent); }

/* ============ 9. 动效与响应式 ============ */
@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  .js-ready [data-reveal] {
    opacity: 0;
    transform: translate3d(0, 14px, 0);
    transition: opacity 0.32s ease, transform 0.32s ease;
  }
  .js-ready [data-reveal].is-visible {
    opacity: 1;
    transform: none;
  }
}

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

@media (max-width: 1120px) {
  .header-frame { grid-template-columns: minmax(0, 196px) 1fr auto; }
  .nav-link { padding: 0 var(--space-2); }
  .action-link { padding: 0 var(--space-2); }
}

@media (max-width: 980px) {
  :root { --section-y: 64px; --section-y-lg: 80px; }

  .header-frame {
    grid-template-columns: 1fr auto;
    min-height: 66px;
  }
  .brand { grid-column: 1; grid-row: 1; padding-right: var(--space-2); }
  .header-actions { grid-column: 2; grid-row: 1; border-left: 0; }
  .header-actions .action-link { display: none; }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    grid-column: 1 / -1;
    grid-row: 2;
    display: none;
    flex-direction: column;
    padding-bottom: var(--space-3);
    border-top: var(--border-thin) solid var(--color-ink);
  }
  .site-nav[data-open="true"] { display: flex; }
  .nav-list { flex-direction: column; flex-wrap: nowrap; }
  .nav-list > li { display: block; }
  .nav-link {
    padding: var(--space-3) var(--space-1);
    border-left: 0;
    border-bottom: var(--border-thin) solid var(--color-line);
  }
  .nav-link[aria-current="page"] { border-bottom-color: var(--color-primary); }
  .nav-slot { display: flex; flex-direction: column; gap: var(--space-1); padding-top: var(--space-2); }

  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .span-3,
  .span-4,
  .span-5 { grid-column: span 2; }

  .footer-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); padding-top: var(--space-4); }
  .side-index { position: static; }

  .media--offset { margin-left: 0; }
}

@media (max-width: 640px) {
  .grid { grid-template-columns: minmax(0, 1fr); }
  .span-1,
  .span-2,
  .span-3,
  .span-4,
  .span-5,
  .span-6 { grid-column: span 1; }

  .header-strip-inner { font-size: var(--text-sm); }
  .strip-meta { display: none; }
  .brand-note { display: none; }

  .footer-inner { grid-template-columns: minmax(0, 1fr); gap: var(--space-3); }
  .footer-base { flex-direction: column; align-items: flex-start; }

  .breadcrumb { font-size: var(--text-sm); }
}