:root {
  --color-surface: #fafafa;
  --color-surface-alt: #f1f1f2;
  --color-surface-deep: #e4e5e6;
  --color-ink: #434951;
  --color-ink-soft: #676f79;
  --color-ink-muted: #767e89;
  --color-line: #d9dadc;
  --color-primary: #3576ca;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dee8f3;
  --color-accent: #2034df;
  --color-accent-ink: #ffffff;
  --color-highlight: #d3d6f5;
  --color-focus: #132aec;
  --color-contrast-surface: #131920;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #41464c;
  --color-contrast-accent: #6c79ea;
  --overlay-scrim: linear-gradient(180deg, rgba(19, 25, 32, 0.35) 0%, rgba(19, 25, 32, 0.72) 55%, rgba(19, 25, 32, 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: 12.2px;
  --text-sm: 14.6px;
  --text-base: 16px;
  --text-lg: 19.2px;
  --text-xl: 23.0px;
  --text-2xl: 27.6px;
  --text-3xl: 33.2px;
  --text-4xl: 39.8px;
  --text-display: clamp(43px, 8.9vw, 114px);
  --text-figure: clamp(36px, 6.4vw, 82px);
  --weight-heading: 650;
  --weight-body: 400;
  --leading-body: 1.77;
  --leading-heading: 1.27;
  --tracking-heading: -0.005em;
  --radius-sm: 14px;
  --radius-md: 15px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(67, 73, 81, 0.08);
  --shadow-2: 0 18px 44px rgba(67, 73, 81, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1240px;
  --measure: 68ch;
  --gutter: 16px;
  --section-y: 112px;
  --section-y-lg: 157px;
}

/* ============================================================
   01 基础重置
   ============================================================ */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface);
  background-image:
    radial-gradient(1180px 600px at 84% -10%, color-mix(in srgb, var(--color-primary) 34%, transparent), transparent 62%),
    radial-gradient(900px 520px at 2% 18%, color-mix(in srgb, var(--color-accent) 13%, transparent), transparent 58%),
    radial-gradient(760px 460px at 46% 104%, color-mix(in srgb, var(--color-primary) 18%, transparent), transparent 64%),
    linear-gradient(180deg, color-mix(in srgb, var(--color-primary) 9%, var(--color-surface)) 0%, var(--color-surface) 46%, var(--color-surface-alt) 100%);
  background-attachment: fixed;
  background-repeat: no-repeat;
}

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

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

ul,
ol { margin: 0; padding: 0; }

hr { border: 0; }

main { display: block; }
main:focus { outline: none; }

:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 4px;
}

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

/* ============================================================
   02 中文排版
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-2);
  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;
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p { margin: 0 0 var(--space-2); }
p:last-child { margin-bottom: 0; }

a {
  color: var(--color-primary);
  text-decoration-color: color-mix(in srgb, var(--color-primary) 42%, transparent);
  text-underline-offset: 3px;
  transition: color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              text-decoration-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

a:hover { color: var(--color-accent); text-decoration-color: var(--color-accent); }

strong { font-weight: 650; }

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

code, kbd, samp {
  font-family: var(--font-mono);
  font-size: 0.94em;
  background: var(--color-surface-deep);
  border-radius: 4px;
  padding: 1px 5px;
}

/* 强调机制：色块高亮 / 彩色下划线 */
.hl {
  background: linear-gradient(transparent 60%, color-mix(in srgb, var(--color-highlight) 94%, transparent) 60%);
  color: inherit;
  padding: 0 0.12em;
}

.ul-accent {
  text-decoration: underline;
  text-decoration-color: var(--color-accent);
  text-decoration-thickness: 2px;
  text-underline-offset: 5px;
}

/* ============================================================
   03 布局基元
   ============================================================ */
.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-8); }

.section__index {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-3);
}

.section__index::after {
  content: "";
  width: 44px;
  height: var(--border-thin);
  background: repeating-linear-gradient(90deg, var(--color-line) 0 5px, transparent 5px 11px);
}

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

.grid--12 { grid-template-columns: minmax(0, 1fr); }

.col-4, .col-5, .col-7, .col-8, .col-12 { grid-column: 1 / -1; }

@media (min-width: 900px) {
  .grid--12 {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: var(--gutter);
    row-gap: var(--space-4);
  }
  .col-4 { grid-column: span 4; }
  .col-5 { grid-column: span 5; }
  .col-7 { grid-column: span 7; }
  .col-8 { grid-column: span 8; }
  .col-12 { grid-column: span 12; }
}

/* 刻度分隔语汇：不用横线，用虚线刻度 */
.tick-rule {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-block: var(--space-6);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.tick-rule::before,
.tick-rule::after {
  content: "";
  flex: 1;
  height: var(--border-thin);
  background: repeating-linear-gradient(90deg, var(--color-line) 0 6px, transparent 6px 14px);
}

/* ============================================================
   04 玻璃面板层
   ============================================================ */
.panel {
  position: relative;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 22%, var(--color-line));
  background: color-mix(in srgb, var(--color-surface) 78%, transparent);
  -webkit-backdrop-filter: blur(18px) saturate(152%);
  backdrop-filter: blur(18px) saturate(152%);
  box-shadow:
    inset 0 1px 0 color-mix(in srgb, var(--color-primary-ink) 58%, transparent),
    var(--shadow-1);
}

.panel--tint {
  background: color-mix(in srgb, var(--color-primary-soft) 60%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 32%, var(--color-line));
}

.panel--deep {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
  box-shadow: var(--shadow-2);
}

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

.panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.panel__title {
  margin: 0;
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
}

.panel__body { margin: 0; }

/* 档案标签 / 金属铭牌编号 */
.meta-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.07em;
  line-height: 1.4;
  color: var(--color-ink-muted);
  background: var(--color-surface-deep);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 92%, transparent);
  border-radius: 4px;
  white-space: nowrap;
}

.meta-chip--accent {
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent-ink) 30%, transparent);
}

.meta-chip--primary {
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary-ink) 30%, transparent);
}

/* 印章 */
.stamp {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 66px;
  height: 66px;
  padding: 6px;
  border-radius: var(--radius-pill);
  border: 2px solid var(--color-accent);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.3;
  text-align: center;
}

/* ============================================================
   05 按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px var(--space-3);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.4;
  color: var(--color-ink);
  text-decoration: none;
  background: color-mix(in srgb, var(--color-surface) 76%, transparent);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 92%, transparent);
  border-radius: var(--radius-sm);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  cursor: pointer;
  transition: transform 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              box-shadow 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              background-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.btn:hover {
  transform: translateY(-2px);
  color: var(--color-ink);
  box-shadow: var(--shadow-1);
  border-color: color-mix(in srgb, var(--color-primary) 55%, transparent);
}

.btn--primary {
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary-ink) 26%, transparent);
}

.btn--primary:hover {
  color: var(--color-primary-ink);
  background: color-mix(in srgb, var(--color-primary) 88%, var(--color-accent));
}

.btn--accent {
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent-ink) 26%, transparent);
}

.btn--accent:hover {
  color: var(--color-accent-ink);
  background: color-mix(in srgb, var(--color-accent) 86%, var(--color-contrast-surface));
}

.btn--ghost { background: transparent; }

/* ============================================================
   06 正文与面包屑
   ============================================================ */
.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.prose > * + * { margin-top: var(--space-3); }
.prose h2 { margin-top: var(--space-6); font-size: var(--text-2xl); }
.prose h3 { margin-top: var(--space-4); font-size: var(--text-xl); }
.prose ul, .prose ol { padding-left: 1.4em; }
.prose li + li { margin-top: 6px; }

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

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  margin-bottom: var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  list-style: none;
}

.breadcrumb li { display: inline-flex; align-items: center; gap: var(--space-1); }
.breadcrumb li + li::before { content: "/"; color: var(--color-line); }
.breadcrumb a { color: var(--color-ink-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--color-primary); }

/* ============================================================
   07 图片容器（供页面阶段放置图片）
   ============================================================ */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--color-surface-deep);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 84%, transparent);
}

.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.03);
}

.media--wide { aspect-ratio: 16 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }

.media__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.media__body {
  position: absolute;
  inset-inline: 0;
  bottom: 0;
  padding: var(--space-3);
  color: var(--color-contrast-ink);
}

.media__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-contrast-ink);
}

.media__meta {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.07em;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

/* ============================================================
   08 头部：左侧纵向索引轨道
   ============================================================ */
.skip-link {
  position: absolute;
  top: -88px;
  left: var(--space-3);
  z-index: 120;
  padding: 10px var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  background: var(--color-contrast-surface);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: top 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

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

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 110;
  pointer-events: none;
  background: transparent;
}

.progress-bar__fill {
  display: block;
  width: 0;
  height: 100%;
  background: var(--color-accent);
  transition: width 140ms linear;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: color-mix(in srgb, var(--color-surface) 80%, transparent);
  -webkit-backdrop-filter: blur(16px) saturate(158%);
  backdrop-filter: blur(16px) saturate(158%);
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 86%, transparent);
  box-shadow: var(--shadow-1);
}

.masthead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
}

.masthead__brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  text-decoration: none;
  color: inherit;
}

.masthead__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary-ink) 34%, transparent);
  box-shadow: var(--shadow-1);
}

.masthead__words { display: block; min-width: 0; }

.masthead__name {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  line-height: 1.25;
}

.masthead__sub {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  line-height: 1.4;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 8px 14px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-soft);
  background: color-mix(in srgb, var(--color-surface) 82%, transparent);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-line) 92%, transparent);
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              background-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.nav-toggle:hover {
  color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 48%, transparent);
}

.nav-toggle__bars {
  position: relative;
  display: inline-block;
  width: 18px;
  height: 10px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.5px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 220ms cubic-bezier(0.2, 0.7, 0.2, 1),
              top 220ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { top: 8px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 4px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 4px; transform: rotate(-45deg); }

.nav-toggle__text { line-height: 1; }

/* 轨道本体 */
.rail {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  padding-inline: var(--space-3);
  transition: max-height 300ms cubic-bezier(0.2, 0.7, 0.2, 1),
              opacity 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              padding-bottom 300ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.rail[data-open="true"] {
  max-height: 78vh;
  opacity: 1;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding-bottom: var(--space-3);
}

.rail__caption {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: var(--color-ink-muted);
}

.rail__list {
  display: grid;
  gap: 4px;
  list-style: none;
  padding-bottom: var(--space-2);
}

.rail__item { margin: 0; }

.rail__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: var(--space-2);
  padding: 10px var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  transition: transform 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              background-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.rail__link:hover {
  transform: translateY(-2px);
  color: var(--color-ink);
  background: color-mix(in srgb, var(--color-primary-soft) 72%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 34%, transparent);
}

.rail__index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 30px;
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.5;
  color: var(--color-ink-muted);
  background: var(--color-surface-deep);
  border-radius: 4px;
}

.rail__label { min-width: 0; }

.rail__link[aria-current="page"] {
  color: var(--color-primary-ink);
  background: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary-ink) 36%, transparent);
  box-shadow: var(--shadow-1);
}

.rail__link[aria-current="page"] .rail__index {
  color: var(--color-primary-ink);
  background: color-mix(in srgb, var(--color-primary-ink) 24%, transparent);
}

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

.rail__note {
  margin: 0;
  padding-top: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  border-top: var(--border-thin) dashed color-mix(in srgb, var(--color-line) 90%, transparent);
}

/* 桌面端：左侧固定纵向轨道 */
@media (min-width: 1024px) {
  body { padding-left: calc(var(--space-8) * 3.5); }

  .progress-bar { left: calc(var(--space-8) * 3.5); }

  .site-header {
    position: fixed;
    inset: 0 auto 0 0;
    width: calc(var(--space-8) * 3.5);
    display: flex;
    flex-direction: column;
    padding: var(--space-4) var(--space-3);
    overflow-y: auto;
    border-bottom: 0;
    border-right: var(--border-thin) solid color-mix(in srgb, var(--color-line) 88%, transparent);
    background: color-mix(in srgb, var(--color-surface) 72%, transparent);
  }

  .skip-link { left: calc(var(--space-8) * 3.5 + var(--space-3)); }

  .masthead {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
    padding: 0 0 var(--space-3);
    border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 72%, transparent);
  }

  .nav-toggle { display: none; }

  .rail {
    max-height: none;
    opacity: 1;
    overflow: visible;
    padding-inline: 0;
    padding-top: var(--space-3);
    flex: 1 1 auto;
  }

  .rail__list { padding-bottom: var(--space-3); }
}

/* ============================================================
   09 页脚：深色阶梯
   ============================================================ */
.site-footer {
  margin-top: var(--section-y);
  color: var(--color-contrast-ink);
  background: var(--color-contrast-surface);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

.footer-stair {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-8) var(--space-3) var(--space-6);
}

.footer-tier {
  padding-block: var(--space-4);
}

.footer-tier--index { padding-block-start: 0; }

.footer-heading {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin: 0 0 var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 400;
  letter-spacing: 0.22em;
  color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent);
}

.footer-heading::before {
  content: "";
  width: 30px;
  height: 2px;
  flex: none;
  background: var(--color-contrast-accent);
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: var(--space-1) var(--space-3);
  list-style: none;
}

.footer-link {
  display: inline-block;
  padding-bottom: 2px;
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.footer-link:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}

.footer-ops {
  display: grid;
  gap: 6px;
  max-width: var(--measure);
  list-style: none;
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  list-style: none;
}

.footer-note {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.05em;
  line-height: 1.7;
  color: color-mix(in srgb, var(--color-contrast-ink) 60%, transparent);
}

@media (min-width: 768px) {
  .footer-tier--ops { padding-left: var(--space-6); }
  .footer-tier--legal { padding-left: calc(var(--space-6) * 2); }
}

/* ============================================================
   10 动效与无障碍
   ============================================================ */
@media (prefers-reduced-motion: no-preference) {
  html.has-js [data-reveal] {
    opacity: 0;
    transform: translate3d(0, 14px, 0);
    transition: opacity 320ms cubic-bezier(0.2, 0.7, 0.2, 1),
                transform 320ms cubic-bezier(0.2, 0.7, 0.2, 1);
  }

  html.has-js [data-reveal][data-revealed="true"] {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html.has-js [data-reveal] { opacity: 1; transform: none; }

  .progress-bar__fill { transition: none; }
}

/* 打印简洁化 */
@media print {
  .site-header,
  .progress-bar,
  .site-footer { display: none; }
  body { padding-left: 0; background: var(--color-surface); }
}