:root {
  --color-surface: #fafafa;
  --color-surface-alt: #f0f0f0;
  --color-surface-deep: #e2e2e2;
  --color-ink: #363031;
  --color-ink-soft: #665c5d;
  --color-ink-muted: #827879;
  --color-line: #d7d6d6;
  --color-primary: #e21d37;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #f7dbdf;
  --color-accent: #e51a35;
  --color-accent-ink: #ffffff;
  --color-highlight: #f6d2d7;
  --color-focus: #df0c28;
  --color-contrast-surface: #190c0e;
  --color-contrast-ink: #e7e4e5;
  --color-contrast-line: #463c3d;
  --color-contrast-accent: #e83149;
  --overlay-scrim: linear-gradient(180deg, rgba(25, 12, 14, 0.35) 0%, rgba(25, 12, 14, 0.72) 55%, rgba(25, 12, 14, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 9.5px;
  --text-sm: 13.5px;
  --text-base: 16px;
  --text-lg: 22.6px;
  --text-xl: 32.0px;
  --text-2xl: 45.2px;
  --text-3xl: 64.0px;
  --text-4xl: 90.4px;
  --text-display: clamp(58px, 12.0vw, 153px);
  --text-figure: clamp(48px, 8.6vw, 110px);
  --weight-heading: 827;
  --weight-body: 400;
  --leading-body: 1.73;
  --leading-heading: 1.26;
  --tracking-heading: -0.015em;
  --radius-sm: 0px;
  --radius-md: 0px;
  --radius-lg: 0px;
  --radius-pill: 0px;
  --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: 1200px;
  --measure: 66ch;
  --gutter: 32px;
  --section-y: 87px;
  --section-y-lg: 122px;
}

/* ==========================================================================
   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;
  padding: 0;
}

ul, ol { list-style: none; }

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

hr { border: 0; }

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

/* ==========================================================================
   2. 中文排版底座
   ========================================================================== */
body {
  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);
  letter-spacing: 0;
  padding-top: 92px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  text-wrap: balance;
}

p { text-wrap: pretty; }

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

[id] { scroll-margin-top: 120px; }

main { display: block; }

@media (max-width: 1024px) {
  body { padding-top: 80px; }
}

/* ==========================================================================
   3. 焦点与可访问性
   ========================================================================== */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.skip-link {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 400;
  display: inline-block;
  padding: 11px 20px;
  background: 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: 0.04em;
  transform: translateY(-140%);
  transition: transform 160ms ease-out;
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline-offset: -4px;
}

/* ==========================================================================
   4. 容器与栅格
   ========================================================================== */
.container {
  width: min(100% - 48px, var(--container));
  margin-inline: auto;
}

@media (max-width: 640px) {
  .container { width: min(100% - 32px, var(--container)); }
}

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

@media (max-width: 900px) {
  .grid-12 {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: var(--space-3);
  }
}

@media (max-width: 560px) {
  .grid-12 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-3);
  }
}

/* ==========================================================================
   5. 分节、刻度与细实线
   ========================================================================== */
.section {
  padding-block: var(--section-y);
  position: relative;
}

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

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

.rule {
  display: block;
  width: 100%;
  height: var(--border-thin);
  background: var(--color-line);
  border: 0;
}

.section-head {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: var(--space-4);
  align-items: start;
  margin-bottom: var(--space-6);
}

.section-head__index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  padding-top: 0.5em;
  transition: color 200ms ease-out;
}

.section-head__title {
  font-size: var(--text-2xl);
  color: var(--color-ink);
}

.section-head__note {
  grid-column: 2;
  margin-top: var(--space-2);
  max-width: var(--measure);
  color: var(--color-ink-soft);
  font-size: var(--text-base);
}

[data-section][data-inview="true"] .section-head__index {
  color: var(--color-primary);
}

[data-section][data-inview="true"] .section-head__title {
  position: relative;
}

[data-section][data-inview="true"] .section-head__title::before {
  content: "";
  position: absolute;
  left: -20px;
  top: 0.42em;
  width: 6px;
  height: 6px;
  background: var(--color-primary);
}

@media (max-width: 720px) {
  .section-head {
    grid-template-columns: 1fr;
    gap: var(--space-1);
  }
  .section-head__note { grid-column: 1; }
  [data-section][data-inview="true"] .section-head__title::before { display: none; }
}

.scale {
  display: block;
  height: var(--space-4);
  border-bottom: var(--border-thin) solid var(--color-line);
  background-image: repeating-linear-gradient(90deg, var(--color-line) 0 1px, transparent 1px 16px);
  background-size: 16px 8px;
  background-repeat: repeat-x;
  background-position: 0 0;
}

.scale--deep {
  border-bottom-color: var(--color-contrast-line);
  background-image: repeating-linear-gradient(90deg, var(--color-contrast-line) 0 1px, transparent 1px 16px);
}

/* ==========================================================================
   6. 文字与数字工具
   ========================================================================== */
.prose {
  max-width: var(--measure);
}

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

.prose h2 {
  font-size: var(--text-xl);
  margin-top: var(--space-6);
}

.prose h3 {
  font-size: var(--text-lg);
  margin-top: var(--space-4);
}

.prose ul,
.prose ol {
  padding-left: var(--space-4);
}

.prose li { list-style: disc; }
.prose ol li { list-style: decimal; }
.prose li + li { margin-top: var(--space-1); }

.prose a {
  border-bottom: var(--border-thin) solid var(--color-primary);
  padding-bottom: 1px;
}

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

.prose code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  background: var(--color-surface-alt);
  padding: 2px 5px;
}

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.01em;
}

.u-display {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-display);
  line-height: 0.92;
  letter-spacing: -0.04em;
}

.u-figure {
  font-family: var(--font-mono);
  font-weight: var(--weight-heading);
  font-size: var(--text-figure);
  line-height: 0.88;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

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

.pullquote {
  position: relative;
  margin: 0;
  padding: var(--space-3) var(--space-4) var(--space-3) calc(var(--space-6) + var(--space-1));
  border-left: 3px solid var(--color-primary);
  background: var(--color-primary-soft);
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-ink);
}

.pullquote::before {
  content: "\201C";
  position: absolute;
  left: var(--space-3);
  top: var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1;
  color: var(--color-primary);
}

/* ==========================================================================
   7. 深底对比区块
   ========================================================================== */
.contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.contrast h1,
.contrast h2,
.contrast h3,
.contrast h4 { color: var(--color-contrast-ink); }

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

.contrast .section-head__index,
.contrast .eyebrow { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }

.contrast .rule,
.contrast hr { background: var(--color-contrast-line); }

.contrast .num,
.contrast .u-figure { color: var(--color-contrast-accent); }

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

.contrast .btn {
  border-color: color-mix(in srgb, var(--color-contrast-ink) 45%, transparent);
  color: var(--color-contrast-ink);
}

.contrast .btn:hover {
  background: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-ink);
}

[data-section].contrast[data-inview="true"] .section-head__index { color: var(--color-contrast-accent); }
[data-section].contrast[data-inview="true"] .section-head__title::before { background: var(--color-contrast-accent); }

/* ==========================================================================
   8. 媒体容器（供页面阶段放置图片）
   ========================================================================== */
.media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--color-surface-deep);
  aspect-ratio: 16 / 9;
}

.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--21x9 { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }

.media > img,
.media > svg,
.media > video,
.media > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
}

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

.media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 2;
  padding: var(--space-3) var(--space-4);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.5;
}

.media__tag {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 2;
  padding: 5px 10px;
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
}

/* ==========================================================================
   9. 按钮 / 面包屑
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 12px 22px;
  border: var(--border-thin) solid var(--color-ink);
  background: transparent;
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.04em;
  border-radius: var(--radius-sm);
  transition: background-color 150ms ease-out, color 150ms ease-out, border-color 150ms ease-out;
}

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

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

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

.btn--ghost {
  border-color: var(--color-line);
  color: var(--color-ink-soft);
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.crumbs__sep { color: var(--color-line); }
.crumbs a:hover { color: var(--color-primary); }
.crumbs [aria-current="page"] { color: var(--color-ink); }

/* ==========================================================================
   10. 站点头部：悬浮浮岛导航
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 300;
  padding: var(--space-2) 0 var(--space-3);
  pointer-events: none;
}

.read-progress {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: color-mix(in srgb, var(--color-line) 70%, transparent);
}

.read-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--color-primary);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 120ms linear;
}

.site-header__island {
  pointer-events: auto;
  width: min(100% - 32px, var(--container));
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 10px var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  transition: padding 200ms ease-out, border-color 200ms ease-out;
}

.site-header[data-scrolled="true"] .site-header__island {
  padding-block: 6px;
  border-color: color-mix(in srgb, var(--color-line) 60%, var(--color-ink-muted));
}

/* 品牌 */
.brand {
  display: flex;
  flex-direction: column;
  justify-content: center;
  flex: 0 0 auto;
  padding-right: var(--space-3);
  border-right: var(--border-thin) solid var(--color-line);
}

.brand__mark {
  display: block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: calc(var(--text-base) * 1.15);
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--color-ink);
}

.brand__note {
  display: block;
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.3;
  color: var(--color-ink-muted);
}

.site-header[data-scrolled="true"] .brand__note { display: none; }

/* 导航 */
.site-nav {
  flex: 1 1 auto;
  min-width: 0;
  display: block;
}

.site-nav__list {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-1);
}

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 8px 12px 9px;
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
  white-space: nowrap;
  transition: color 150ms ease-out;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 3px;
  height: var(--border-thin);
  background: var(--color-line);
  transition: height 150ms ease-out, background-color 150ms ease-out;
}

.site-nav__link:hover { color: var(--color-ink); }
.site-nav__link:hover::after {
  height: 2px;
  background: var(--color-primary);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-ink);
  font-weight: var(--weight-heading);
}

.site-nav__link[aria-current="page"]::after {
  height: 2px;
  background: var(--color-primary);
}

.site-nav__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 50%;
  width: 5px;
  height: 5px;
  margin-top: -2.5px;
  background: var(--color-primary);
}

/* 右侧文本入口 */
.header-cta {
  flex: 0 0 auto;
  padding: 7px 12px;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.04em;
  color: var(--color-ink);
  border-bottom: 2px solid var(--color-primary);
  transition: background-color 150ms ease-out, color 150ms ease-out;
}

.header-cta:hover {
  background: var(--color-primary);
  color: var(--color-primary-ink);
}

/* 移动按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  flex: 0 0 auto;
  margin-left: auto;
  padding: 9px 12px;
  border: var(--border-thin) solid var(--color-line);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.06em;
  transition: background-color 150ms ease-out, color 150ms ease-out, border-color 150ms ease-out;
}

.nav-toggle__icon {
  position: relative;
  width: 16px;
  height: 10px;
  display: block;
}

.nav-toggle__icon::before,
.nav-toggle__icon::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.5px;
  background: currentColor;
  transition: transform 180ms ease-out;
}

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

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

.nav-toggle[aria-expanded="true"] .nav-toggle__icon::before { transform: translateY(4.25px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__icon::after { transform: translateY(-4.25px) rotate(-45deg); }

/* 平板 / 手机 */
@media (max-width: 1024px) {
  .site-header__island { gap: var(--space-2); padding-inline: var(--space-2); }
  .brand { padding-right: var(--space-2); }
  .header-cta { display: none; }
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: fixed;
    left: 16px;
    right: 16px;
    top: 78px;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    display: none;
    background: var(--color-surface);
    border: var(--border-thin) solid var(--color-line);
    padding: var(--space-2);
  }

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

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
  }

  .site-nav__link {
    display: block;
    padding: 15px 14px;
    font-family: var(--font-heading);
    font-size: var(--text-lg);
    font-weight: var(--weight-heading);
    letter-spacing: -0.01em;
    color: var(--color-ink);
    border-bottom: var(--border-thin) solid var(--color-line);
  }

  .site-nav__link::after { display: none; }

  .site-nav__link:hover {
    background: var(--color-surface-alt);
    color: var(--color-ink);
  }

  .site-nav__link[aria-current="page"] {
    background: var(--color-primary);
    color: var(--color-primary-ink);
    border-bottom-color: var(--color-primary);
  }

  .site-nav__link[aria-current="page"]::before {
    left: auto;
    right: 16px;
    margin-top: -2.5px;
    background: var(--color-primary-ink);
  }

  .site-nav__item:last-child .site-nav__link { border-bottom: 0; }
}

@media (max-width: 480px) {
  .brand__note { display: none; }
  .nav-toggle__label { display: none; }
}

/* ==========================================================================
   11. 站点页脚：线框刻度收口
   ========================================================================== */
.site-footer {
  margin-top: var(--space-8);
  border-top: var(--border-thin) solid var(--color-line);
  background: var(--color-surface);
}

.footer-scale {
  height: var(--space-4);
  border-bottom: var(--border-thin) solid var(--color-line);
  background-image: repeating-linear-gradient(90deg, var(--color-line) 0 1px, transparent 1px 24px);
  background-size: 24px 9px;
  background-repeat: repeat-x;
  background-position: 0 0;
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 5fr) minmax(0, 3fr);
  gap: var(--space-6) var(--gutter);
  padding-block: var(--space-8) var(--space-6);
}

.footer-brand__mark {
  display: inline-block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--color-ink);
  border-bottom: 2px solid var(--color-primary);
  padding-bottom: 4px;
}

.footer-brand__note {
  margin-top: var(--space-2);
  max-width: 40ch;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.footer-nav__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-2);
  padding-bottom: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.footer-nav__list,
.footer-legal__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.footer-nav a,
.footer-legal a {
  position: relative;
  display: inline-block;
  padding-left: 14px;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  transition: color 150ms ease-out;
}

.footer-nav a::before,
.footer-legal a::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 4px;
  height: 4px;
  background: var(--color-line);
  transition: background-color 150ms ease-out;
}

.footer-nav a:hover,
.footer-legal a:hover { color: var(--color-ink); }

.footer-nav a:hover::before,
.footer-legal a:hover::before { background: var(--color-primary); }

.footer-nav a[aria-current="page"],
.footer-legal a[aria-current="page"] {
  color: var(--color-ink);
  font-weight: var(--weight-heading);
}

.footer-nav a[aria-current="page"]::before,
.footer-legal a[aria-current="page"]::before { background: var(--color-primary); }

.footer-registry {
  border-top: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
}

.footer-registry__inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-4);
  padding-block: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.9;
  color: var(--color-ink-muted);
}

.footer-registry__item { white-space: nowrap; }
.footer-registry__item--addr { white-space: normal; }

@media (max-width: 900px) {
  .site-footer__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-4) var(--gutter);
    padding-block: var(--space-6) var(--space-4);
  }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 560px) {
  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr);
    padding-block: var(--space-4);
  }
  .footer-brand { grid-column: auto; }
}

/* ==========================================================================
   12. 减弱动效
   ========================================================================== */
@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;
  }

  .read-progress__bar { transition: none; }
}