/* ==========================================================================
   万博看台 · 共享样式 /assets/site.css
   看台深墨绿底 + 暖纸档案 + 印刷标签，数据叙事型骨架
   ========================================================================== */

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

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

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

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

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

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

a { color: #5CF2B0; text-decoration-thickness: 1px; text-underline-offset: 3px; }

::selection { background: #5CF2B0; color: #071A14; }

/* 2. 变量 ------------------------------------------------------------------ */
:root {
  --ink: #071A14;
  --ink-2: #0E2A22;
  --mint: #5CF2B0;
  --amber: #F4B942;
  --coral: #FF6B5B;
  --paper: #F3EBDC;
  --print: #111A18;
  --moss: #8FB6A5;
  --slate: #182628;

  --font-title: "Archivo Narrow", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", ui-monospace, "Courier New", monospace;
  --font-body: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-serif: "Noto Serif SC", Georgia, "Songti SC", serif;

  --wrap: 1240px;
  --gutter: clamp(16px, 4vw, 40px);
  --line-mint: rgba(92, 242, 176, 0.16);
  --line-paper: rgba(243, 235, 220, 0.22);
  --radius: 2px;
}

/* 3. 基础排版 -------------------------------------------------------------- */
body {
  background-color: var(--ink);
  background-image:
    radial-gradient(1200px 520px at 10% -10%, rgba(92, 242, 176, 0.10), transparent 60%),
    radial-gradient(900px 420px at 92% -4%, rgba(244, 185, 66, 0.07), transparent 62%);
  background-repeat: no-repeat;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  font-feature-settings: "kern" 1;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-title);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(34px, 5.4vw, 46px); }
h2 { font-size: clamp(26px, 3.8vw, 34px); }
h3 { font-size: clamp(20px, 2.8vw, 24px); }

p { line-height: 1.8; }

.mono, .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.muted { color: var(--moss); }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--mint);
}

.lede {
  font-size: clamp(16px, 1.6vw, 18px);
  color: rgba(243, 235, 220, 0.86);
  max-width: 62ch;
}

.hairline {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, transparent, rgba(143, 182, 165, 0.4), transparent);
}

/* 4. 布局容器 -------------------------------------------------------------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.site-main { display: block; }

.section { padding-block: clamp(40px, 7vw, 88px); }
.section--tight { padding-block: clamp(26px, 4vw, 48px); }
.section--ink { background: var(--ink); }
.section--paper { background: var(--paper); color: var(--print); }
.section--paper a { color: #0E6B4D; }
.section--paper .eyebrow { color: #0E6B4D; }
.section--paper .muted { color: #4E6459; }

.grid { display: grid; gap: clamp(14px, 2.2vw, 24px); }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.grid--4 { grid-template-columns: repeat(auto-fit, minmax(168px, 1fr)); }

/* 5. 焦点与跳转 ------------------------------------------------------------ */
:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: 3px;
  border-radius: var(--radius);
}

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -70px;
  z-index: 300;
  display: inline-block;
  padding: 0.6em 1.1em;
  background: var(--amber);
  color: var(--print);
  font-family: var(--font-title);
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--radius);
  transition: top 0.18s ease-out;
}

.skip-link:focus { top: 10px; }

/* 6. 按钮 / 标签 / 卡片 ---------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 0.7em 1.15em;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-family: var(--font-title);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}

.btn:hover { transform: translateY(-1px); }
.btn--amber { background: var(--amber); color: var(--print); }
.btn--amber:hover { background: #FFCB63; }
.btn--mint { background: var(--mint); color: var(--ink); }
.btn--ghost { background: transparent; border-color: rgba(92, 242, 176, 0.45); color: var(--mint); }
.btn--ghost:hover { border-color: var(--mint); background: rgba(92, 242, 176, 0.08); }
.btn--paper { background: var(--paper); color: var(--print); }
.btn--block { width: 100%; justify-content: center; }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 0.22em 0.6em;
  border: 1px solid rgba(143, 182, 165, 0.45);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--moss);
  background: rgba(24, 38, 40, 0.6);
}

.tag--mint { border-color: rgba(92, 242, 176, 0.5); color: var(--mint); }
.tag--amber { border-color: rgba(244, 185, 66, 0.55); color: var(--amber); }
.tag--coral { border-color: rgba(255, 107, 91, 0.55); color: var(--coral); }

.card {
  position: relative;
  padding: clamp(16px, 2.2vw, 24px);
  background: var(--ink-2);
  border: 1px solid var(--line-mint);
  border-radius: var(--radius);
}

.card--paper {
  background: var(--paper);
  color: var(--print);
  border-color: rgba(17, 26, 24, 0.16);
  box-shadow: 4px 4px 0 rgba(7, 26, 20, 0.55), 8px 8px 0 rgba(143, 182, 165, 0.12);
}

.card--paper a { color: #0E6B4D; }
.card--paper .muted { color: #4E6459; }

.panel {
  padding: clamp(16px, 2.4vw, 26px);
  background: var(--slate);
  border: 1px solid var(--line-mint);
  border-radius: var(--radius);
}

/* 7. 章节编号体系 ---------------------------------------------------------- */
.chapter { position: relative; }

.chapter-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: clamp(10px, 1.6vw, 18px);
  margin-bottom: clamp(16px, 2.4vw, 28px);
}

.chapter__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(30px, 6vw, 56px);
  font-weight: 700;
  line-height: 0.9;
  color: var(--mint);
  letter-spacing: -0.02em;
}

.chapter__kicker {
  display: block;
  font-family: var(--font-serif);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--moss);
  margin-bottom: 4px;
}

.chapter__title {
  font-family: var(--font-title);
  font-size: clamp(22px, 3.4vw, 30px);
  color: var(--paper);
}

.section--paper .chapter__title { color: var(--print); }
.section--paper .chapter__num { color: #0E6B4D; }

[data-chapter] { transition: opacity 0.3s ease; }

[data-chapter].is-current .chapter__num { color: var(--amber); }

[data-chapter].is-current .chapter__title::after {
  content: "";
  display: block;
  width: 42px;
  height: 2px;
  margin-top: 8px;
  background: var(--coral);
}

/* 8. 数据与标签组件 -------------------------------------------------------- */
.stat {
  display: grid;
  gap: 2px;
  padding-left: 12px;
  border-left: 2px solid rgba(92, 242, 176, 0.45);
}

.stat__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 3vw, 28px);
  font-weight: 700;
  color: var(--mint);
  line-height: 1.1;
}

.stat__label {
  font-size: 13px;
  color: var(--moss);
}

.stat--live { border-left-color: var(--coral); }
.stat--live .stat__num { color: var(--coral); }

.chip {
  display: inline-flex;
  align-items: center;
  padding: 0.34em 0.8em;
  border: 1px solid rgba(143, 182, 165, 0.45);
  border-radius: var(--radius);
  background: transparent;
  color: var(--moss);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: color 0.16s ease, border-color 0.16s ease, background-color 0.16s ease;
}

.chip:hover { color: var(--mint); border-color: var(--mint); }
.chip[aria-pressed="true"] {
  background: var(--mint);
  border-color: var(--mint);
  color: var(--ink);
  font-weight: 600;
}

/* 9. 折叠面板（问答 / 术语） ---------------------------------------------- */
.accordion { display: grid; gap: 10px; }

.accordion__item {
  background: var(--ink-2);
  border: 1px solid var(--line-mint);
  border-radius: var(--radius);
}

.accordion__trigger {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  width: 100%;
  padding: 14px 16px;
  background: transparent;
  border: 0;
  text-align: left;
  font-family: var(--font-title);
  font-size: 17px;
  font-weight: 700;
  color: var(--paper);
  cursor: pointer;
}

.accordion__trigger::after {
  content: "+";
  font-family: var(--font-mono);
  color: var(--mint);
}

.accordion__item[data-open] .accordion__trigger::after { content: "–"; }

.accordion__panel {
  display: none;
  padding: 0 16px 16px;
  color: rgba(243, 235, 220, 0.82);
  font-size: 15px;
}

.accordion__item[data-open] .accordion__panel { display: block; }

/* 10. 正文与面包屑 --------------------------------------------------------- */
.prose { max-width: 70ch; }
.prose p + p { margin-top: 1em; }
.prose ul, .prose ol { margin: 1em 0; padding-left: 1.2em; list-style: disc; }

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5em;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--moss);
}

.breadcrumbs li { display: inline-flex; align-items: center; gap: 0.5em; }
.breadcrumbs li + li::before { content: "/"; color: rgba(143, 182, 165, 0.6); }
.breadcrumbs a { color: var(--moss); text-decoration: none; }
.breadcrumbs a:hover { color: var(--mint); }
.breadcrumbs [aria-current="page"] { color: var(--paper); }

/* 11. 图像容器（页面阶段放图） ------------------------------------------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line-mint);
  border-radius: var(--radius);
  background: linear-gradient(140deg, var(--ink-2), #05120E);
}

.media-frame img,
.media-frame svg {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.82) contrast(1.06) brightness(0.94);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(7, 26, 20, 0.05) 40%, rgba(7, 26, 20, 0.78));
}

.media-frame--wide { aspect-ratio: 16 / 7; }
.media-frame--hero { aspect-ratio: 16 / 9; }
.media-frame--card { aspect-ratio: 4 / 3; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }

.media-frame__cap {
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 10px;
  z-index: 2;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--paper);
}

.media-frame__tag { position: absolute; top: 10px; left: 10px; z-index: 2; }

.media-grid {
  display: grid;
  gap: clamp(10px, 1.8vw, 18px);
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
}

/* 12. 头部 ----------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  color: var(--paper);
  background: rgba(7, 26, 20, 0.94);
  border-bottom: 1px solid var(--line-mint);
  -webkit-backdrop-filter: blur(10px) saturate(1.2);
  backdrop-filter: blur(10px) saturate(1.2);
}

.progress-rail {
  height: 3px;
  background: rgba(143, 182, 165, 0.16);
}

.progress-bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--mint), var(--amber));
  transition: width 0.12s linear;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 12px var(--gutter);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
  color: var(--paper);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  align-content: center;
  gap: 3px;
  flex: none;
  width: 36px;
  height: 36px;
  padding: 7px;
  border-radius: var(--radius);
  background: linear-gradient(150deg, var(--mint), rgba(92, 242, 176, 0.28));
}

.brand-mark span {
  display: block;
  height: 4px;
  border-radius: 1px;
  background: var(--ink);
}

.brand-mark span:nth-child(1) { width: 100%; }
.brand-mark span:nth-child(2) { width: 68%; }
.brand-mark span:nth-child(3) { width: 40%; }

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

.brand-name {
  display: block;
  font-family: var(--font-title);
  font-size: clamp(18px, 2.4vw, 22px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: 0.02em;
}

.brand-tagline {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.35;
  letter-spacing: 0.04em;
  color: var(--moss);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  background: rgba(14, 42, 34, 0.9);
  border: 1px solid rgba(92, 242, 176, 0.35);
  border-radius: var(--radius);
  color: var(--mint);
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
}

.nav-toggle-bars { display: grid; gap: 3px; width: 16px; }
.nav-toggle-bars i { display: block; height: 2px; background: currentColor; }
.nav-toggle-bars i:nth-child(3) { width: 10px; }

.site-nav { display: flex; align-items: center; gap: clamp(14px, 2vw, 28px); }

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 20px);
  counter-reset: navitem;
}

.nav-list li { display: flex; counter-increment: navitem; }

.nav-list a {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 0.45em;
  padding: 0.4em 0.1em;
  color: var(--paper);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
}

.nav-list a::before {
  content: counter(navitem, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--moss);
}

.nav-list a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -3px;
  height: 2px;
  background: var(--mint);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.2s ease-out;
}

.nav-list a:hover { color: var(--mint); }
.nav-list a:hover::after,
.nav-list a:focus-visible::after { transform: scaleX(1); }

.nav-list a[aria-current="page"] { color: var(--mint); }
.nav-list a[aria-current="page"]::before { color: var(--amber); }
.nav-list a[aria-current="page"]::after { transform: scaleX(1); background: var(--amber); }

.nav-utility { display: flex; align-items: center; gap: 10px; }

.nav-cta { font-size: 14px; padding: 0.6em 1em; }

.header-strip {
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 22px);
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 7px var(--gutter);
  border-top: 1px solid rgba(92, 242, 176, 0.1);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--moss);
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
}

.header-strip::-webkit-scrollbar { display: none; }

.strip-item { display: inline-flex; align-items: center; gap: 7px; }
.strip-item--mono { color: var(--mint); }
.strip-item--mute { color: rgba(143, 182, 165, 0.75); }

.strip-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--coral);
  animation: strip-pulse 2.6s ease-out infinite;
}

.strip-link {
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid rgba(244, 185, 66, 0.5);
}

.strip-link:hover { color: #FFCB63; }

@keyframes strip-pulse {
  0% { box-shadow: 0 0 0 0 rgba(255, 107, 91, 0.55); }
  70% { box-shadow: 0 0 0 7px rgba(255, 107, 91, 0); }
  100% { box-shadow: 0 0 0 0 rgba(255, 107, 91, 0); }
}

@keyframes nav-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}

/* 13. 页脚 ----------------------------------------------------------------- */
.site-footer {
  position: relative;
  margin-top: clamp(40px, 6vw, 80px);
  color: var(--paper);
  background: linear-gradient(180deg, var(--ink) 0%, var(--ink-2) 46%, #0A2019 100%);
  border-top: 1px solid rgba(92, 242, 176, 0.2);
}

.footer-layers {
  position: absolute;
  left: 0;
  right: 0;
  top: -8px;
  height: 8px;
  display: flex;
  gap: 6px;
  padding-inline: var(--gutter);
  pointer-events: none;
}

.footer-layers span {
  flex: 1;
  border-top: 1px solid rgba(243, 235, 220, 0.2);
  background: rgba(243, 235, 220, 0.08);
}

.footer-layers span:nth-child(2) { background: rgba(243, 235, 220, 0.15); }
.footer-layers span:nth-child(3) { background: rgba(243, 235, 220, 0.24); }

.footer-inner {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(30px, 5vw, 56px) var(--gutter) clamp(20px, 3vw, 34px);
}

.footer-top {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
  grid-template-columns: 1fr;
}

.footer-brand-line {
  font-family: var(--font-title);
  font-size: clamp(19px, 2.4vw, 24px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: 0.01em;
}

.footer-lede {
  margin-top: 10px;
  max-width: 36ch;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--moss);
}

.footer-stamp {
  margin-top: 14px;
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: rgba(143, 182, 165, 0.85);
}

.footer-col-title {
  margin-bottom: 12px;
  font-family: var(--font-serif);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.footer-list { display: grid; gap: 9px; }

.footer-list a {
  color: rgba(243, 235, 220, 0.88);
  font-size: 14.5px;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.footer-list a:hover { color: var(--mint); border-bottom-color: rgba(92, 242, 176, 0.5); }

.contact-list { display: grid; gap: 10px; }
.contact-row { display: grid; gap: 2px; }

.contact-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--moss);
}

.contact-value {
  font-size: 14.5px;
  color: var(--paper);
  overflow-wrap: anywhere;
}

.copy-btn {
  margin-top: 14px;
  padding: 0.6em 1em;
  background: transparent;
  border: 1px solid rgba(92, 242, 176, 0.45);
  border-radius: var(--radius);
  color: var(--mint);
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.copy-btn:hover { background: rgba(92, 242, 176, 0.1); }
.copy-btn.is-copied {
  background: var(--mint);
  border-color: var(--mint);
  color: var(--ink);
}

.footer-bottom {
  border-top: 1px solid rgba(143, 182, 165, 0.18);
  background: rgba(4, 16, 12, 0.55);
}

.footer-bottom-inner {
  display: grid;
  gap: 8px;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 18px var(--gutter) 26px;
  font-size: 12.5px;
  color: var(--moss);
}

.footer-legal a {
  color: var(--moss);
  text-decoration: none;
  border-bottom: 1px solid rgba(143, 182, 165, 0.4);
}

.footer-legal a:hover { color: var(--mint); }

.footer-icp { font-family: var(--font-mono); letter-spacing: 0.06em; }

.footer-region { max-width: 68ch; line-height: 1.7; }

/* 14. 返回顶部（页面放置按钮） -------------------------------------------- */
.to-top {
  position: fixed;
  right: clamp(12px, 3vw, 28px);
  bottom: clamp(12px, 3vw, 28px);
  z-index: 90;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  background: rgba(14, 42, 34, 0.94);
  border: 1px solid rgba(92, 242, 176, 0.4);
  border-radius: var(--radius);
  color: var(--mint);
  font-family: var(--font-mono);
  font-size: 12px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s;
}

.to-top.is-visible { opacity: 1; visibility: visible; transform: none; }

/* 15. 断点 ----------------------------------------------------------------- */
@media (min-width: 760px) {
  .footer-top { grid-template-columns: 1.4fr 1fr 1fr; }
}

@media (min-width: 900px) {
  .footer-bottom-inner {
    grid-template-columns: auto auto 1fr;
    align-items: baseline;
    gap: 20px;
  }
  .footer-region { justify-self: end; text-align: right; }
}

@media (min-width: 960px) {
  .nav-toggle { display: none; }
}

@media (min-width: 1080px) {
  .footer-top { grid-template-columns: 1.5fr 0.9fr 0.9fr 1.2fr; }
}

@media (max-width: 959px) {
  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-height: calc(100vh - 90px);
    overflow-y: auto;
    padding: 6px var(--gutter) 18px;
    background: var(--ink-2);
    border-bottom: 1px solid rgba(92, 242, 176, 0.22);
    box-shadow: 0 18px 30px rgba(0, 0, 0, 0.45);
  }

  .site-header[data-open] .site-nav {
    display: flex;
    animation: nav-in 0.2s ease-out;
  }

  .site-header[data-open] .nav-toggle {
    background: var(--mint);
    color: var(--ink);
    border-color: var(--mint);
  }

  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }

  .nav-list li { border-bottom: 1px dashed rgba(143, 182, 165, 0.22); }

  .nav-list a {
    width: 100%;
    padding: 14px 2px;
    font-size: 17px;
    white-space: normal;
  }

  .nav-list a::after { display: none; }
  .nav-list a[aria-current="page"] { padding-left: 8px; border-left: 2px solid var(--amber); }

  .nav-utility { padding-top: 16px; }
  .nav-cta { width: 100%; justify-content: center; }
}

@media (max-width: 640px) {
  .brand-tagline { display: none; }
  .strip-item--mute { display: none; }
  .media-frame--wide { aspect-ratio: 4 / 3; }
}

@media (max-width: 420px) {
  .nav-toggle-label { display: none; }
}

/* 16. 动效降级 ------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .btn:hover { transform: none; }
  .strip-dot { animation: none; }
}