:root {
  --color-surface: #f4f3f3;
  --color-surface-alt: #eceaea;
  --color-surface-deep: #e0dede;
  --color-ink: #4e4140;
  --color-ink-soft: #776564;
  --color-ink-muted: #897776;
  --color-line: #d6d3d3;
  --color-primary: #cf3b30;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #efd9d8;
  --color-accent: #e52415;
  --color-accent-ink: #ffffff;
  --color-highlight: #f1cecb;
  --color-focus: #d91708;
  --color-contrast-surface: #2b1918;
  --color-contrast-ink: #e7e4e4;
  --color-contrast-line: #544645;
  --color-contrast-accent: #ed4c3f;
  --overlay-scrim: linear-gradient(180deg, rgba(43, 25, 24, 0.35) 0%, rgba(43, 25, 24, 0.72) 55%, rgba(43, 25, 24, 0.92) 100%);
  --font-heading: "Kaiti SC", STKaiti, KaiTi, "Songti SC", serif;
  --font-body: "Songti SC", "PingFang SC", "Microsoft YaHei", serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 11.7px;
  --text-sm: 15.6px;
  --text-base: 18px;
  --text-lg: 24.0px;
  --text-xl: 32.0px;
  --text-2xl: 42.6px;
  --text-3xl: 56.8px;
  --text-4xl: 75.8px;
  --text-display: clamp(40px, 8.1vw, 104px);
  --text-figure: clamp(33px, 5.9vw, 75px);
  --weight-heading: 494;
  --weight-body: 400;
  --leading-body: 1.87;
  --leading-heading: 1.26;
  --tracking-heading: 0.025em;
  --radius-sm: 2px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --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: 1060px;
  --measure: 63ch;
  --gutter: 24px;
  --section-y: 109px;
  --section-y-lg: 153px;
}

/* 派生令牌（不覆盖、不重名于上方任何变量） */
:root {
  --rail-w: 168px;
  --rail-scale-step: 18px;
  --dur-reveal: 420ms;
  --dur-stamp: 180ms;
  --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1);
}

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

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

body {
  margin: 0;
  min-height: 100%;
  background-color: var(--color-surface);
  background-image:
    radial-gradient(140% 90% at 6% -12%, color-mix(in srgb, var(--color-surface-deep) 72%, transparent) 0%, transparent 58%),
    radial-gradient(110% 70% at 98% 4%, color-mix(in srgb, var(--color-surface-alt) 92%, transparent) 0%, transparent 62%),
    radial-gradient(90% 60% at 48% 110%, color-mix(in srgb, var(--color-surface-deep) 56%, transparent) 0%, transparent 60%);
  background-repeat: no-repeat;
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  text-rendering: optimizeLegibility;
  -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);
  text-wrap: balance;
}

p, figure, blockquote, dl, dd { margin: 0; }
ol, ul { margin: 0; padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
img { height: auto; }
button { font: inherit; color: inherit; }
table { border-collapse: collapse; width: 100%; }

a { color: var(--color-ink); text-decoration-thickness: 1px; text-underline-offset: 4px; text-decoration-color: var(--color-line); }
a:hover { color: var(--color-primary); text-decoration-color: var(--color-primary); }

[hidden] { display: none !important; }

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

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

main { display: block; }

/* ---------- 文字与排版工具 ---------- */
.num,
time,
.meta-line,
.stamp__num { font-family: var(--font-mono); }
.num { font-size: 0.94em; letter-spacing: 0.02em; }

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

.lede {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.7;
  color: var(--color-ink);
}

.prose {
  max-width: var(--measure);
  color: var(--color-ink-soft);
}
.prose p + p { margin-top: var(--space-3); }
.prose strong { color: var(--color-ink); font-weight: var(--weight-heading); }

.meta-line {
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.tag {
  display: inline-block;
  padding: 2px var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
  background-color: color-mix(in srgb, var(--color-surface-deep) 82%, transparent);
  border-radius: var(--radius-sm);
}

.aside-note {
  position: relative;
  max-width: var(--measure);
  padding-left: var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
}
.aside-note::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 1px;
  background-color: var(--color-primary);
}

.stack { display: grid; gap: var(--space-3); }
.stack--lg { gap: var(--space-6); }

/* ---------- 容器与栅格 ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

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

@media (min-width: 768px) {
  .col-3 { grid-column: span 3; }
  .col-4 { grid-column: span 4; }
  .col-6 { grid-column: span 6; }
  .col-8 { grid-column: span 8; }
  .col-9 { grid-column: span 9; }
  .col-12 { grid-column: span 12; }
}

/* ---------- 章节（墨阶推进） ---------- */
.chapter { padding-block: var(--section-y); }
.chapter--tight { padding-block: var(--space-8); }
.chapter--lg { padding-block: var(--section-y-lg); }
.chapter--alt { background-color: var(--color-surface-alt); }
.chapter--deep { background-color: var(--color-surface-deep); }

.chapter__head {
  display: grid;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}

.chapter__kicker {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.chapter__index {
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--color-primary);
}

.chapter__title { font-size: var(--text-2xl); }

.chapter__note {
  max-width: var(--measure);
  color: var(--color-ink-soft);
}

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

/* ---------- 框景外壳 ---------- */
.frame {
  position: relative;
  padding: clamp(var(--space-3), 4vw, var(--space-8));
}
.frame::before,
.frame::after {
  content: "";
  position: absolute;
  width: 26px;
  height: 26px;
  pointer-events: none;
}
.frame::before {
  top: 0;
  left: 0;
  border-top: var(--border-thin) solid var(--color-line);
  border-left: var(--border-thin) solid var(--color-line);
}
.frame::after {
  right: 0;
  bottom: 0;
  border-right: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  line-height: 1.2;
  text-decoration: none;
  color: var(--color-ink);
  background-color: var(--color-surface-deep);
  border-radius: var(--radius-sm);
  transition: background-color 200ms var(--ease-out), color 200ms var(--ease-out);
}
.btn:hover {
  color: var(--color-ink);
  background-color: color-mix(in srgb, var(--color-surface-deep) 62%, var(--color-ink-muted));
}

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

.btn--quiet {
  padding: var(--space-1) 0;
  background-color: transparent;
  color: var(--color-ink);
}
.btn--quiet::after {
  content: "→";
  font-family: var(--font-mono);
  color: var(--color-primary);
}
.btn--quiet:hover { background-color: transparent; color: var(--color-primary); }

/* ---------- 印章与数字块 ---------- */
.stamp {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1);
  padding: 2px var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-primary-ink);
  background-color: var(--color-primary);
  border-radius: var(--radius-sm);
}
.stamp--soft { color: var(--color-primary); background-color: var(--color-primary-soft); }
.stamp__num { font-size: var(--text-xs); letter-spacing: 0.08em; }

.num-block { display: grid; gap: var(--space-1); }
.num-block__value {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--color-ink);
}
.num-block__unit {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
}
.num-block__caption {
  max-width: 36ch;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
}

/* ---------- 面板与反相区块 ---------- */
.panel {
  padding: var(--space-4);
  background-color: var(--color-surface-deep);
  border-radius: var(--radius-md);
}
.panel--plain { padding: 0; background-color: transparent; }

.block-contrast {
  padding: var(--space-6);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-md);
}
.block-contrast h2,
.block-contrast h3 { color: var(--color-contrast-ink); }
.block-contrast .meta-line,
.block-contrast .num-block__caption { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }
.block-contrast .stamp { background-color: var(--color-contrast-accent); color: var(--color-contrast-ink); }
.block-contrast a { color: var(--color-contrast-ink); text-decoration-color: var(--color-contrast-line); }

/* ---------- 图片容器基础规则 ---------- */
.figure { margin: 0; }
.figure__media {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background-color: var(--color-surface-deep);
  border-radius: var(--radius-sm);
}
.figure__media img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.04) brightness(1.02);
  transition: filter 320ms var(--ease-out), scale 420ms var(--ease-out);
}
.figure--tone .figure__media img { filter: grayscale(1) sepia(0.26) saturate(1.15) contrast(1.06); }
.figure--wide .figure__media { aspect-ratio: 16 / 9; }
.figure--tall .figure__media { aspect-ratio: 3 / 4; }
.figure--scrim .figure__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
}
.figure__caption {
  margin-top: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
}
.figure__over {
  position: absolute;
  inset-inline: 0;
  bottom: 0;
  z-index: 2;
  padding: var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.4;
  color: var(--color-contrast-ink);
}
.figure a:hover img { scale: 1.02; }

/* ---------- 筛选 ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}
.filter-btn {
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-ink-soft);
  background-color: transparent;
  border: 0;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color 200ms var(--ease-out), background-color 200ms var(--ease-out);
}
.filter-btn:hover { color: var(--color-ink); }
.filter-btn[aria-pressed="true"] { color: var(--color-primary-ink); background-color: var(--color-primary); }
.filter-bar__count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* ---------- 问答 ---------- */
.qa { display: grid; gap: var(--space-4); }
.qa__item { padding-bottom: var(--space-4); }
.qa__item + .qa__item { padding-top: var(--space-2); }
.qa__trigger {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  width: 100%;
  padding: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.5;
  text-align: left;
  color: var(--color-ink);
  background-color: transparent;
  border: 0;
  cursor: pointer;
}
.qa__trigger::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  color: var(--color-primary);
}
.qa__item[data-open] .qa__trigger::after { content: "–"; }
.qa__num { font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-ink-muted); }
.qa__panel {
  margin-top: var(--space-3);
  max-width: var(--measure);
  color: var(--color-ink-soft);
}

/* ---------- 面包屑 ---------- */
.breadcrumb { padding-top: var(--space-6); }
.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}
.breadcrumb__list > li + li::before { content: "/"; margin-right: var(--space-2); color: var(--color-line); }
.breadcrumb__link { color: var(--color-ink-soft); text-decoration: none; }
.breadcrumb__link:hover { color: var(--color-primary); }

/* ---------- 跳至正文 ---------- */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 90;
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  background-color: var(--color-contrast-surface);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transform: translateY(-220%);
  transition: transform 180ms var(--ease-out);
}
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 头部：移动端为顶部条 + 抽屉 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  padding-top: env(safe-area-inset-top, 0px);
  background-color: color-mix(in srgb, var(--color-surface) 92%, var(--color-surface-deep));
  color: var(--color-ink);
}

.rail {
  position: relative;
  z-index: 2;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-3);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-3) var(--gutter);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex: 1 1 auto;
  min-width: 0;
  color: inherit;
  text-decoration: none;
}
.brand:hover { color: var(--color-ink); }
.brand-mark {
  display: grid;
  place-items: center;
  flex: none;
  inline-size: 36px;
  block-size: 36px;
  font-family: var(--font-heading);
  font-size: var(--text-base);
  color: var(--color-primary-ink);
  background-color: var(--color-primary);
  border-radius: var(--radius-sm);
}
.brand-text { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.2;
  letter-spacing: var(--tracking-heading);
}
.brand-sub {
  display: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.quarter-stamp {
  order: 3;
  flex: 1 1 100%;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-2);
  background-color: var(--color-primary-soft);
  border-radius: var(--radius-sm);
  animation: stamp-down var(--dur-stamp) var(--ease-out) both;
}
.quarter-stamp__label {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-primary);
}
.quarter-stamp__value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}
.quarter-stamp__time {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

@keyframes stamp-down {
  from { scale: 1.04; }
  to { scale: 1; }
}

.nav-toggle {
  order: 2;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink);
  background-color: transparent;
  border: 0;
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.nav-toggle__bars {
  position: relative;
  display: block;
  flex: none;
  inline-size: 20px;
  block-size: 12px;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: currentColor;
  transition: transform 220ms var(--ease-out);
}
.nav-toggle__bars::before { top: 2px; }
.nav-toggle__bars::after { bottom: 2px; }
.site-header[data-open] .nav-toggle__bars::before { transform: translateY(4px) rotate(45deg); }
.site-header[data-open] .nav-toggle__bars::after { transform: translateY(-4px) rotate(-45deg); }

.site-nav {
  order: 4;
  display: none;
  flex: 1 1 100%;
  padding-block: var(--space-2) var(--space-3);
}
.site-header[data-open] .site-nav { display: block; }
.site-nav__list { display: flex; flex-direction: column; gap: var(--space-1); }
.site-nav__link {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: color 180ms var(--ease-out), background-color 180ms var(--ease-out);
}
.site-nav__link::before {
  content: "";
  flex: none;
  inline-size: 5px;
  block-size: 5px;
  border-radius: 50%;
  background-color: var(--color-line);
  transform: translateY(-2px);
}
.site-nav__link:hover {
  color: var(--color-ink);
  background-color: color-mix(in srgb, var(--color-surface-deep) 62%, transparent);
}
.site-nav__index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}
.site-nav__link[aria-current="page"] { color: var(--color-ink); }
.site-nav__link[aria-current="page"]::before {
  background-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-soft);
}
.site-nav__link[aria-current="page"] .site-nav__index { color: var(--color-primary); }

.rail-cta {
  display: inline-flex;
  justify-content: center;
  margin-top: var(--space-3);
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  color: var(--color-primary-ink);
  background-color: var(--color-primary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: background-color 200ms var(--ease-out);
}
.rail-cta:hover { color: var(--color-primary-ink); background-color: var(--color-accent); }

.rail-scale { display: none; }

.rail-progress {
  position: fixed;
  inset-inline: 0;
  top: 0;
  z-index: 60;
  height: 2px;
  background-color: transparent;
  pointer-events: none;
}
.rail-progress__fill {
  display: block;
  height: 100%;
  width: var(--progress, 0%);
  background-color: var(--color-primary);
  transition: width 120ms linear;
}

/* ---------- 头部：桌面端左侧季度轨道 ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }

  .site-header {
    position: fixed;
    inset-block: 0;
    inset-inline-start: 0;
    width: var(--rail-w);
    padding-top: 0;
    background-color: var(--color-surface);
  }

  .rail {
    flex-direction: column;
    flex-wrap: nowrap;
    align-items: stretch;
    height: 100%;
    max-width: none;
    margin: 0;
    padding: var(--space-8) var(--space-3) var(--space-6);
    gap: var(--space-6);
  }

  .brand { flex: 0 0 auto; flex-direction: column; align-items: flex-start; }
  .brand-sub { display: block; max-width: 15ch; line-height: 1.6; }

  .quarter-stamp {
    order: 0;
    flex: 0 0 auto;
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
    padding: var(--space-2);
    background-color: var(--color-primary);
    color: var(--color-primary-ink);
    transform: rotate(-1.2deg);
  }
  .quarter-stamp__label,
  .quarter-stamp__value { color: var(--color-primary-ink); }
  .quarter-stamp__time {
    margin-left: 0;
    color: color-mix(in srgb, var(--color-primary-ink) 76%, transparent);
    line-height: 1.6;
  }

  .nav-toggle { display: none; }

  .site-nav {
    display: block;
    order: 0;
    flex: 1 1 auto;
    min-height: 0;
    overflow-y: auto;
    padding-block: 0;
  }
  .site-nav__link { font-size: var(--text-base); padding: var(--space-1) 0; }
  .rail-cta { width: 100%; }

  .rail-scale {
    display: block;
    position: absolute;
    inset-block: 0;
    inset-inline-end: 0;
    width: 1px;
    background-image: repeating-linear-gradient(
      to bottom,
      var(--color-line) 0 1px,
      transparent 1px var(--rail-scale-step)
    );
  }

  .rail-progress {
    inset-inline: auto;
    inset-block: 0;
    inset-inline-start: calc(var(--rail-w) - 2px);
    width: 2px;
    height: auto;
  }
  .rail-progress__fill {
    width: 100%;
    height: var(--progress, 0%);
    transition: height 120ms linear;
  }
}

@media (min-width: 480px) {
  .brand-sub { display: block; }
}

/* ---------- 页脚：卡片式面板 ---------- */
.site-footer {
  margin-top: var(--section-y);
  padding-block: var(--space-8) var(--space-4);
  background-color: var(--color-surface-deep);
  color: var(--color-ink);
}

.footer-inner {
  display: grid;
  gap: var(--space-8);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-brand { display: grid; gap: var(--space-2); }
.footer-brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  line-height: 1.2;
  letter-spacing: var(--tracking-heading);
}
.footer-brand__sub {
  max-width: 52ch;
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-ink-soft);
}
.footer-brand__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.8;
  color: var(--color-ink-muted);
}

.footer-panels { display: grid; gap: var(--space-4); }

.footer-panel {
  display: grid;
  gap: var(--space-2);
  align-content: start;
  padding: var(--space-4);
  background-color: color-mix(in srgb, var(--color-surface) 72%, transparent);
  border-radius: var(--radius-md);
}
.footer-panel__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  color: var(--color-ink);
}
.footer-panel__list { display: grid; gap: var(--space-2); }
.footer-panel__item {
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-ink-soft);
}
.footer-panel__note {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
}
.footer-link {
  color: var(--color-ink);
  text-decoration: none;
}
.footer-link::after {
  content: " ↗";
  font-family: var(--font-mono);
  font-size: 0.86em;
  color: var(--color-primary);
}
.footer-link:hover { color: var(--color-primary); }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  width: 100%;
  max-width: var(--container);
  margin: var(--space-8) auto 0;
  padding: var(--space-3) var(--gutter) 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.8;
  color: var(--color-ink-muted);
}

@media (min-width: 768px) {
  .footer-panels { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  .footer-inner { gap: var(--space-6); }
  .footer-brand__sub { max-width: 62ch; }
}

/* ---------- 显现 ---------- */
[data-reveal] {
  transition: opacity var(--dur-reveal) var(--ease-out), transform var(--dur-reveal) var(--ease-out);
}
[data-js="on"] [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
}
[data-js="on"] [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 降低动效偏好 ---------- */
@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;
  }

  [data-js="on"] [data-reveal] { opacity: 1; transform: none; }
  .quarter-stamp { transform: none; }
  .figure a:hover img { scale: 1; }
}