:root {
  --color-surface: #fbfbfb;
  --color-surface-alt: #f2f2f2;
  --color-surface-deep: #e5e6e6;
  --color-ink: #444950;
  --color-ink-soft: #686e78;
  --color-ink-muted: #787e87;
  --color-line: #dadbdc;
  --color-primary: #4b73b4;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e2e8f1;
  --color-accent: #d22d5e;
  --color-accent-ink: #ffffff;
  --color-highlight: #f4d6df;
  --color-focus: #da2057;
  --color-contrast-surface: #1a1e25;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #464a50;
  --color-contrast-accent: #db577e;
  --overlay-scrim: linear-gradient(180deg, rgba(26, 30, 37, 0.35) 0%, rgba(26, 30, 37, 0.72) 55%, rgba(26, 30, 37, 0.92) 100%);
  --font-heading: "Songti SC", "Source Han Serif SC", "Noto Serif SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, 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(34px, 5.2vw, 67px);
  --text-figure: clamp(28px, 3.8vw, 48px);
  --weight-heading: 700;
  --weight-body: 400;
  --leading-body: 1.86;
  --leading-heading: 1.3;
  --tracking-heading: 0.007em;
  --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: 1060px;
  --measure: 64ch;
  --gutter: 16px;
  --section-y: 88px;
  --section-y-lg: 123px;
}

/* ---------- reset & 中文排版 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main { display: block; }

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

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;
}

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

ul, ol { margin: 0 0 var(--space-2); padding-left: 1.25em; }
li { margin-bottom: 4px; }

a {
  color: var(--color-ink);
  text-decoration: underline;
  text-decoration-color: var(--color-line);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.18s ease, text-decoration-color 0.18s ease;
}
a:hover { color: var(--color-primary); text-decoration-color: var(--color-primary); }

button { font-family: inherit; }

hr,
.rule {
  border: 0;
  border-top: var(--border-thin) solid var(--color-line);
  margin: var(--space-4) 0;
}

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

[id] { scroll-margin-top: 108px; }

/* ---------- 布局 ---------- */
.container {
  width: min(calc(100% - 32px), var(--container));
  margin-inline: auto;
}

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

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

.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; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }

/* ---------- 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: -80px;
  left: var(--space-2);
  z-index: 300;
  padding: 10px var(--space-2);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  text-decoration: none;
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  transition: top 0.18s ease;
}
.skip-link:focus { top: var(--space-2); color: var(--color-contrast-accent); }

/* ---------- 头部：悬浮胶囊浮岛 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  padding: var(--space-2) 0 12px;
  background: var(--color-surface);
}

.header-island {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: min(calc(100% - 32px), var(--container));
  margin-inline: auto;
  padding: 9px 12px;
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--color-ink);
}
.brand:hover { color: var(--color-ink); }

.brand-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  flex: 0 0 auto;
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  line-height: 1;
  border-radius: var(--radius-sm);
}

.brand-text { display: block; min-width: 0; }

.brand-name {
  display: block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.2;
  letter-spacing: 0.08em;
}

.brand-descriptor {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.4;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  background: var(--color-surface);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.nav-toggle:hover { border-color: var(--color-primary); color: var(--color-primary); }

.nav-toggle-bar {
  position: relative;
  display: block;
  width: 14px;
  height: 1px;
  background: currentColor;
}
.nav-toggle-bar::before,
.nav-toggle-bar::after {
  content: "";
  position: absolute;
  left: 0;
  width: 14px;
  height: 1px;
  background: currentColor;
}
.nav-toggle-bar::before { top: -4px; }
.nav-toggle-bar::after { top: 4px; }

.site-nav { margin: 0 auto; }

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.nav-list li { margin: 0; }

.nav-list a {
  display: block;
  padding: 7px 10px;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thick) solid transparent;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.nav-list a:hover {
  color: var(--color-ink);
  background: var(--color-surface-alt);
  border-bottom-color: var(--color-line);
}
.nav-list a[aria-current="page"] {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-bottom-color: var(--color-primary);
}

.header-utility {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.status-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 8px;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  white-space: nowrap;
}
.status-dot {
  width: 6px;
  height: 6px;
  flex: 0 0 auto;
  background: var(--color-accent);
  border-radius: 50%;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 13px;
  font-size: var(--text-sm);
  line-height: 1.4;
  letter-spacing: 0.04em;
  color: var(--color-ink);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.btn:hover { color: var(--color-primary); border-color: var(--color-primary); background: var(--color-primary-soft); }

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

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

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

/* ---------- 章节与标题 ---------- */
.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-6); }
.section--alt {
  background: var(--color-surface-alt);
  border-block: var(--border-thin) solid var(--color-line);
}
.section--deep {
  background: var(--color-surface-deep);
  border-block: var(--border-thin) solid var(--color-line);
}
.section--dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-block: var(--border-thin) solid var(--color-contrast-line);
}
.section--dark h1,
.section--dark h2,
.section--dark h3 { color: var(--color-contrast-ink); }
.section--dark a { color: var(--color-contrast-ink); text-decoration-color: var(--color-contrast-line); }
.section--dark a:hover { color: var(--color-contrast-accent); text-decoration-color: var(--color-contrast-accent); }

.eyebrow {
  display: block;
  margin-bottom: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--color-primary);
}
.section--dark .eyebrow { color: var(--color-contrast-accent); }

.section-head { margin-bottom: var(--space-4); }
.section-title {
  font-size: var(--text-3xl);
  margin: 0 0 var(--space-2);
}
.section-title--sm { font-size: var(--text-2xl); }

.lede {
  max-width: var(--measure);
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
}
.section--dark .lede { color: var(--color-contrast-ink); }

.page-head {
  padding-block: var(--space-6) var(--space-4);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.page-title {
  font-size: var(--text-4xl);
  margin: 0 0 var(--space-2);
}

.prose { max-width: var(--measure); }
.prose h2 { font-size: var(--text-2xl); margin-top: var(--space-4); }
.prose h3 { font-size: var(--text-xl); margin-top: var(--space-3); }
.prose li { margin-bottom: 6px; }
.prose--narrow { max-width: 52ch; }

/* ---------- 要点框 ---------- */
.note {
  max-width: 52ch;
  margin-block: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-left: var(--border-thick) solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.note-title {
  margin: 0 0 6px;
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-primary);
}
.note p { font-size: var(--text-sm); color: var(--color-ink-soft); }

.note--alert {
  background: var(--color-highlight);
  border-left-color: var(--color-accent);
}
.note--alert .note-title { color: var(--color-accent); }
.note--alert p { color: var(--color-ink); }

.note--dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
  border-left-color: var(--color-contrast-accent);
}
.note--dark .note-title { color: var(--color-contrast-accent); }
.note--dark p { color: var(--color-contrast-ink); }

/* ---------- 目录与面包屑 ---------- */
.toc {
  padding: var(--space-3);
  background: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}
.toc-title {
  margin: 0 0 var(--space-2);
  padding-bottom: 8px;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.toc-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: toc;
}
.toc-list li {
  margin: 0;
  counter-increment: toc;
}
.toc-list a {
  display: flex;
  gap: 10px;
  padding: 6px 8px;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-left: var(--border-thick) solid transparent;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.toc-list a::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  line-height: 1.8;
}
.toc-list a:hover { color: var(--color-ink); background: var(--color-surface); }
.toc-list a.is-current {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-left-color: var(--color-primary);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 var(--space-3);
  padding: 0;
  list-style: none;
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}
.breadcrumb li { display: flex; align-items: center; gap: 8px; margin: 0; }
.breadcrumb li + li::before { content: "/"; color: var(--color-line); }
.breadcrumb a {
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.breadcrumb a:hover { color: var(--color-primary); border-bottom-color: var(--color-primary); }

/* ---------- 图片容器 ---------- */
.media-figure { margin: 0 0 var(--space-3); }

.media {
  position: relative;
  display: block;
  overflow: hidden;
  width: 100%;
  background: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}
.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.media--strip { aspect-ratio: 21 / 9; }
.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);
}
.media-text {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 1;
  color: var(--color-contrast-ink);
}
.media-text h3,
.media-text .media-text-title {
  color: var(--color-contrast-ink);
  font-size: var(--text-lg);
  margin: 0 0 4px;
}
.media-text p { margin: 0; font-size: var(--text-sm); }

.media-caption {
  display: block;
  padding-top: 6px;
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

/* ---------- 入口卡片 ---------- */
.entry-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.18s ease, background-color 0.18s ease;
}
.entry-card:hover { border-color: var(--color-primary); color: inherit; }

.entry-card__num {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  line-height: 1.1;
  color: var(--color-primary);
  letter-spacing: 0.04em;
}
.entry-card__title {
  margin: 0;
  font-size: var(--text-lg);
}
.entry-card__desc {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}
.entry-card__foot {
  margin-top: auto;
  padding-top: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.entry-card--silver { background: var(--color-surface-deep); }
.entry-card--silver:hover { background: var(--color-surface); }

.entry-card--accent {
  background: var(--color-surface);
  border-left: var(--border-thick) solid var(--color-accent);
}
.entry-card--accent .entry-card__num { color: var(--color-accent); }

.entry-card--dark {
  background: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.entry-card--dark .entry-card__title { color: var(--color-contrast-ink); }
.entry-card--dark .entry-card__desc { color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-contrast-surface)); }
.entry-card--dark .entry-card__num { color: var(--color-contrast-accent); }
.entry-card--dark .entry-card__foot { color: color-mix(in srgb, var(--color-contrast-ink) 60%, var(--color-contrast-surface)); }
.entry-card--dark:hover { border-color: var(--color-contrast-accent); color: var(--color-contrast-ink); }

/* ---------- 标签 ---------- */
.tag {
  display: inline-block;
  padding: 2px 7px;
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  line-height: 1.7;
  color: var(--color-ink-muted);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}
.tag--primary {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-color: var(--color-primary-soft);
}
.tag--accent {
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border-color: var(--color-accent);
}
.tag--dark {
  color: var(--color-contrast-ink);
  background: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
}

/* ---------- 折线式两步路径轴 ---------- */
.step-axis {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: stepax;
}
.step-axis > li {
  margin: 0;
  padding-top: var(--space-2);
  border-top: var(--border-thick) solid var(--color-line);
  transition: border-color 0.5s ease;
}
.step-axis > li::before {
  counter-increment: stepax;
  content: counter(stepax, decimal-leading-zero);
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  transition: color 0.5s ease;
}
.step-axis.is-active > li { border-top-color: var(--color-primary); }
.step-axis.is-active > li::before { color: var(--color-primary); }
.step-axis.is-active > li:nth-child(2),
.step-axis.is-active > li:nth-child(2)::before { transition-delay: 0.18s; }
.step-axis .step-title {
  margin: 0 0 6px;
  font-size: var(--text-lg);
}
.step-axis p {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

/* ---------- 折叠面板与标签切换 ---------- */
.fold {
  margin: 0 0 -1px;
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}
.fold > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: 10px var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-ink);
  list-style: none;
  cursor: pointer;
  transition: background-color 0.18s ease;
}
.fold > summary::-webkit-details-marker { display: none; }
.fold > summary::after {
  content: "＋";
  font-family: var(--font-mono);
  color: var(--color-primary);
}
.fold[open] > summary::after { content: "－"; }
.fold > summary:hover { background: var(--color-primary-soft); }
.fold-body {
  padding: 0 var(--space-3) var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

.tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  margin: 0 0 var(--space-3);
  padding: 0 0 var(--space-2);
  list-style: none;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.tab-list li { margin: 0; }
.tab-btn {
  padding: 6px 12px;
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  color: var(--color-ink-soft);
  background: transparent;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.tab-btn:hover { color: var(--color-ink); background: var(--color-surface-alt); }
.tab-btn[aria-selected="true"] {
  color: var(--color-primary);
  background: var(--color-primary-soft);
  border-color: var(--color-line);
  border-bottom-color: var(--color-primary);
}
.tab-panel[hidden] { display: none; }
.tab-panel:focus-visible { outline: var(--border-thick) solid var(--color-focus); outline-offset: 4px; }

/* ---------- 显现 ---------- */
[data-reveal] { transition: opacity 0.45s ease, transform 0.45s ease; }
[data-reveal].is-hidden { opacity: 0; transform: translateY(8px); }
[data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 页脚 ---------- */
.site-footer {
  margin-top: var(--section-y);
  padding: var(--space-8) 0 var(--space-4);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thick) solid var(--color-contrast-line);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr repeat(3, 1fr) 1.5fr;
  gap: var(--space-4) var(--space-3);
}

.footer-brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  margin-bottom: 10px;
  background: var(--color-contrast-accent);
  color: var(--color-contrast-surface);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  line-height: 1;
  border-radius: var(--radius-sm);
}
.footer-brand-name {
  margin: 0 0 6px;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  letter-spacing: 0.08em;
  color: var(--color-contrast-ink);
}
.footer-brand-desc {
  margin: 0 0 var(--space-2);
  font-size: var(--text-sm);
  line-height: 1.7;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, var(--color-contrast-surface));
}
.footer-region {
  margin: 0;
  display: inline-block;
  padding: 3px 8px;
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
}

.footer-col-title {
  margin: 0 0 var(--space-2);
  padding-bottom: 8px;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.footer-list {
  margin: 0;
  padding: 0;
  list-style: none;
}
.footer-list li { margin: 0; }
.footer-list a {
  display: block;
  padding: 4px 0;
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}
.footer-list a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-line);
}

.footer-col--contact .footer-contact {
  margin: 0 0 6px;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-contrast-surface));
}
.footer-strong { color: var(--color-contrast-ink); }

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-3);
  margin-top: var(--space-6);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}
.footer-meta-item {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface));
}

/* ---------- 响应式 ---------- */
@media (max-width: 1080px) {
  .status-chip { display: none; }
  .header-island { gap: var(--space-2); }
}

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }
  .header-island {
    flex-wrap: wrap;
    row-gap: 10px;
    align-items: center;
  }
  .brand { margin-right: auto; }
  .header-utility { margin-left: auto; }
  .site-nav {
    order: 3;
    flex: 1 0 100%;
    display: none;
    margin: 0;
  }
  .site-nav[data-open="true"] { display: block; }
  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-top: 8px;
    border-top: var(--border-thin) solid var(--color-line);
  }
  .nav-list a {
    padding: 10px 8px;
    border-bottom: 0;
    border-left: var(--border-thick) solid transparent;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  }
  .nav-list a[aria-current="page"] {
    background: var(--color-primary-soft);
    border-left-color: var(--color-primary);
    border-bottom-color: transparent;
  }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
  .grid-12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .col-3, .col-4, .col-5, .col-6 { grid-column: span 6; }
  .col-7, .col-8, .col-12 { grid-column: span 6; }
}

@media (max-width: 640px) {
  .section { padding-block: var(--space-6); }
  .section--lg { padding-block: var(--space-8); }
  .header-island { padding: 8px 10px; }
  .brand-descriptor { display: none; }
  .brand-name { font-size: var(--text-base); }
  .btn { padding: 7px 10px; }
  .grid,
  .grid--2,
  .grid--3,
  .grid--4,
  .step-axis { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-4) 0; }
  .section-title { font-size: var(--text-2xl); }
  .page-title { font-size: var(--text-3xl); }
  .footer-meta { flex-direction: column; align-items: flex-start; gap: 6px; }
}

/* ---------- 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;
  }
  [data-reveal].is-hidden { opacity: 1; transform: none; }
}