:root {
  --color-surface: #f8f8f8;
  --color-surface-alt: #eeeeee;
  --color-surface-deep: #e1e0e0;
  --color-ink: #363030;
  --color-ink-soft: #665c5c;
  --color-ink-muted: #827878;
  --color-line: #d5d4d4;
  --color-primary: #da2c25;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #f4dbda;
  --color-accent: #0a8185;
  --color-accent-ink: #ffffff;
  --color-highlight: #cde3e3;
  --color-focus: #03797d;
  --color-contrast-surface: #291615;
  --color-contrast-ink: #e7e4e4;
  --color-contrast-line: #534343;
  --color-contrast-accent: #12e7ed;
  --overlay-scrim: linear-gradient(180deg, rgba(41, 22, 21, 0.35) 0%, rgba(41, 22, 21, 0.72) 55%, rgba(41, 22, 21, 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: 10.1px;
  --text-sm: 14.3px;
  --text-base: 17px;
  --text-lg: 24.0px;
  --text-xl: 34.0px;
  --text-2xl: 48.1px;
  --text-3xl: 68.0px;
  --text-4xl: 96.1px;
  --text-display: clamp(52px, 10.7vw, 137px);
  --text-figure: clamp(44px, 7.7vw, 99px);
  --weight-heading: 855;
  --weight-body: 400;
  --leading-body: 1.68;
  --leading-heading: 1.17;
  --tracking-heading: -0.022em;
  --radius-sm: 1px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 2px;
  --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: 1260px;
  --measure: 66ch;
  --gutter: 16px;
  --section-y: 75px;
  --section-y-lg: 105px;
}

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

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ul, ol {
  margin: 0;
}

ul, ol { padding: 0; list-style: none; }

img, svg, video, canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

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

button {
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

a { color: inherit; text-decoration: none; }

table { border-collapse: collapse; width: 100%; }

[hidden] { display: none !important; }

/* ============================================================
   2. 基础排版
   ============================================================ */
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: 0.01em;
  overflow-x: hidden;
}

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

h1 { font-size: var(--text-2xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); letter-spacing: 0.01em; }
h4 { font-size: var(--text-base); letter-spacing: 0.02em; }

.display {
  font-size: var(--text-display);
  letter-spacing: 0.01em;
  line-height: 1.02;
}

.figure-number,
.section-num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-body);
  line-height: 1;
  letter-spacing: 0.04em;
  font-variant-numeric: tabular-nums;
}

.section-num { font-size: var(--text-3xl); }

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.04em;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}

.surface-contrast .eyebrow { color: var(--color-contrast-accent); }
.surface-primary .eyebrow,
.surface-accent .eyebrow { color: inherit; opacity: 0.82; }

.lede {
  font-size: var(--text-lg);
  line-height: 1.52;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.surface-contrast .lede {
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
}

.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.prose > * + * { margin-top: var(--space-3); }

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.prose a:hover { color: var(--color-primary); }

.surface-contrast .prose a { color: var(--color-contrast-accent); }

.prose code,
.prose .mono { font-family: var(--font-mono); }

sup { font-size: 0.6em; }

/* ============================================================
   3. 布局容器与区块
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

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

.surface { background-color: var(--color-surface); color: var(--color-ink); }
.surface-alt { background-color: var(--color-surface-alt); color: var(--color-ink); }
.surface-deep { background-color: var(--color-surface-deep); color: var(--color-ink); }

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

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

.surface-contrast {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.surface-contrast .section-num,
.surface-contrast .figure-number { color: var(--color-contrast-accent); }

.surface-primary .section-num,
.surface-primary .figure-number { color: var(--color-primary-ink); }

.surface-accent .section-num,
.surface-accent .figure-number { color: var(--color-accent-ink); }

.section-num { color: var(--color-primary); }

/* ============================================================
   4. 栅格
   ============================================================ */
.grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: var(--gutter);
}

.grid-7 { grid-template-columns: repeat(7, minmax(0, 1fr)); }
.grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.col-2 { grid-column: span 2; }
.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; }

@media (max-width: 1060px) {
  .grid-7 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .col-4, .col-5, .col-6, .col-7 { grid-column: span 4; }
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 920px) {
  .grid-7 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .col-2, .col-3, .col-4, .col-5, .col-6, .col-7 { grid-column: span 2; }
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 560px) {
  .grid, .grid-7, .grid-4, .grid-3, .grid-2 {
    grid-template-columns: minmax(0, 1fr);
  }
  .col-2, .col-3, .col-4, .col-5, .col-6, .col-7 { grid-column: span 1; }
}

/* ============================================================
   5. 通用组件
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.06em;
  line-height: 1.2;
  text-align: center;
  border-radius: var(--radius-md);
  background-color: var(--color-surface-deep);
  color: var(--color-ink);
}

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

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

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

.btn-quiet {
  background-color: color-mix(in srgb, currentColor 14%, transparent);
  color: inherit;
}
.btn-quiet:hover { background-color: color-mix(in srgb, currentColor 24%, transparent); }

.tag {
  display: inline-block;
  padding: 2px var(--space-1);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  line-height: 1.5;
  font-variant-numeric: tabular-nums;
}

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

.tag--accent {
  background-color: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
}

.card {
  padding: var(--space-4);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
}

.card--primary { background-color: var(--color-primary); color: var(--color-primary-ink); }
.card--accent { background-color: var(--color-accent); color: var(--color-accent-ink); }
.card--contrast { background-color: var(--color-contrast-surface); color: var(--color-contrast-ink); }
.card--flat { background-color: transparent; padding: 0; }

.card > * + * { margin-top: var(--space-2); }

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

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
}

.breadcrumb-list li { display: inline-flex; align-items: center; gap: var(--space-1); }
.breadcrumb-list li + li::before { content: "/"; color: var(--color-ink-muted); }
.breadcrumb a:hover { color: var(--color-accent); }

.surface-contrast .breadcrumb { color: color-mix(in srgb, var(--color-contrast-ink) 65%, transparent); }

/* 纵向路径轴 */
.axis {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.axis-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.02em;
}

.axis-item .mono { font-size: var(--text-sm); }
.axis-item:hover { background-color: var(--color-primary-soft); color: var(--color-ink); }

.axis-item.is-active,
.axis-item[aria-current="true"] {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.surface-contrast .axis-item { background-color: color-mix(in srgb, var(--color-contrast-ink) 12%, transparent); color: var(--color-contrast-ink); }
.surface-contrast .axis-item.is-active { background-color: var(--color-contrast-accent); color: var(--color-contrast-surface); }

/* 图片容器：叠色处理 + 文字蒙版 */
.figure { margin: 0; }

.figure-media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  background-color: var(--color-accent);
}

.figure-media--primary { background-color: var(--color-primary); }
.figure-media--contrast { background-color: var(--color-contrast-surface); }
.figure-media--wide { aspect-ratio: 21 / 9; }
.figure-media--square { aspect-ratio: 1 / 1; }
.figure-media--tall { aspect-ratio: 3 / 4; }

.figure-media img,
.figure-media picture,
.figure-media picture img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.06);
  opacity: 0.72;
  mix-blend-mode: luminosity;
}

.figure-overlay {
  position: absolute;
  inset: 0;
  z-index: 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);
}

.figure-overlay h3,
.figure-overlay h4,
.figure-overlay p { color: var(--color-contrast-ink); }

.figure-caption {
  margin-top: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.surface-contrast .figure-caption {
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}

/* 分段切换 */
.tabs { display: block; }

.tablist {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  padding: var(--space-1);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-deep);
}

.surface-contrast .tablist { background-color: color-mix(in srgb, var(--color-contrast-ink) 10%, transparent); }

.tab {
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}

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

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

.surface-contrast .tab { color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent); }
.surface-contrast .tab[aria-selected="true"] { background-color: var(--color-contrast-accent); color: var(--color-contrast-surface); }

.tab-panel { padding-top: var(--space-4); }

/* 折叠条款 */
.collapse {
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
  overflow: hidden;
}

.collapse + .collapse { margin-top: var(--space-1); }

.collapse > summary {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-surface-deep);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.02em;
  cursor: pointer;
  list-style: none;
}

.collapse > summary::-webkit-details-marker { display: none; }
.collapse > summary::after { content: "＋"; font-family: var(--font-mono); color: var(--color-primary); }
.collapse[open] > summary::after { content: "－"; }

.collapse-body {
  padding: var(--space-3);
  max-width: var(--measure);
  color: var(--color-ink-soft);
}

/* 锚点落地高亮 */
#main-content,
section[id] { scroll-margin-top: calc(var(--space-8) + var(--space-3)); }

@keyframes anchor-flash {
  0% { background-color: var(--color-highlight); }
  100% { background-color: transparent; }
}

section[id]:target { animation: anchor-flash 1200ms ease-out; }

/* 焦点与选择 */
:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
}

::selection {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ============================================================
   6. 页头
   ============================================================ */
.skip-link {
  position: absolute;
  left: var(--space-3);
  top: calc(-1 * var(--space-8));
  z-index: 140;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  color: var(--color-ink);
  transition: background-color 200ms linear, color 200ms linear;
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-2) var(--space-3);
  min-height: calc(var(--space-8) + var(--space-1));
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex: 0 0 auto;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: calc(var(--space-4) + var(--space-1));
  height: calc(var(--space-4) + var(--space-1));
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1;
}

.brand-text { display: block; }

.brand-name {
  display: block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.1;
  letter-spacing: 0.06em;
}

.brand-sub {
  display: block;
  margin-top: 2px;
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.primary-nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  display: block;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: inherit;
  white-space: nowrap;
}

.nav-link:hover {
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
}

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

.header-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.header-cta:hover {
  background-color: color-mix(in srgb, var(--color-accent) 80%, var(--color-contrast-surface));
  color: var(--color-accent-ink);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  margin-left: auto;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
}

.nav-toggle-bars {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nav-toggle-bars span {
  display: block;
  height: 2px;
  background-color: currentColor;
}

/* 首屏深色反转页：导航透明叠加 */
body[data-header="overlay"] .site-header:not([data-scrolled="true"]) {
  background-color: transparent;
  color: var(--color-contrast-ink);
}

body[data-header="overlay"] .site-header:not([data-scrolled="true"]) .brand-sub {
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
}

body[data-header="overlay"] .site-header:not([data-scrolled="true"]) .nav-link:hover {
  background-color: color-mix(in srgb, var(--color-contrast-accent) 22%, transparent);
  color: var(--color-contrast-ink);
}

@media (max-width: 1060px) {
  .nav-link { padding: var(--space-1); font-size: var(--text-sm); }
  .header-cta { padding: var(--space-1) var(--space-2); }
}

@media (max-width: 920px) {
  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    margin-left: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-3) var(--space-6);
    background-color: var(--color-surface-deep);
    color: var(--color-ink);
    max-height: 80vh;
    overflow-y: auto;
  }

  .primary-nav[data-open="true"] { display: flex; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
  }

  .nav-link {
    padding: var(--space-2);
    font-size: var(--text-lg);
    letter-spacing: 0.02em;
  }

  .header-cta {
    width: 100%;
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-base);
  }

  .brand-name { font-size: var(--text-base); }
  .brand-mark { width: var(--space-4); height: var(--space-4); font-size: var(--text-base); }
}

@media (max-width: 560px) {
  .header-inner { padding-inline: var(--space-2); }
}

/* ============================================================
   7. 页脚（阶梯式两层）
   ============================================================ */
.site-footer {
  background-color: var(--color-surface-deep);
  color: var(--color-ink);
}

.footer-index-inner {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: var(--gutter);
  padding-block: var(--space-8) var(--space-6);
}

.footer-brand { grid-column: span 3; }
.footer-col { grid-column: span 2; }

.footer-brand-name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: var(--leading-heading);
  letter-spacing: 0.06em;
}

.footer-brand-note {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.footer-col-title {
  margin-bottom: var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.footer-links {
  display: grid;
  gap: var(--space-1);
}

.footer-links a {
  display: inline-block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
}

.footer-links a:hover { color: var(--color-primary); }

.footer-base {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.footer-base-inner {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: var(--gutter);
  padding-block: var(--space-6) var(--space-8);
}

.footer-contact { grid-column: span 4; }

.footer-base .footer-col-title { color: var(--color-contrast-accent); }

.contact-line {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-2);
  margin-bottom: var(--space-1);
}

.contact-key {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.1em;
  color: var(--color-contrast-accent);
  min-width: 5em;
}

.contact-value {
  font-family: var(--font-mono);
  font-size: var(--text-base);
  letter-spacing: 0.04em;
  color: var(--color-contrast-ink);
  word-break: break-word;
}

.footer-legal {
  grid-column: span 3;
  align-self: end;
  text-align: right;
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
}

@media (max-width: 920px) {
  .footer-index-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: span 2; }
  .footer-col { grid-column: span 1; }
  .footer-base-inner { grid-template-columns: minmax(0, 1fr); }
  .footer-contact { grid-column: span 1; }
  .footer-legal { grid-column: span 1; text-align: left; }
}

@media (max-width: 560px) {
  .footer-index-inner { grid-template-columns: minmax(0, 1fr); }
  .footer-brand, .footer-col { grid-column: span 1; }
  .contact-key { min-width: 100%; }
}

/* ============================================================
   8. 动效降级
   ============================================================ */
@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;
    scroll-behavior: auto !important;
  }

  section[id]:target { animation: none; background-color: var(--color-highlight); }
}