/* =========================================================
   视讯厅娱乐 · 共享样式表 /assets/site.css
   墨海蓝底 · 霓虹青导航 · 珊瑚橙行动 · 暖金节点
   ========================================================= */

/* ---------- 01. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

html.is-nav-open,
html.is-nav-open body { overflow: hidden; }

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

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

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

a { color: inherit; }

button { font: inherit; color: inherit; background: none; border: 0; }

/* ---------- 02. Tokens ---------- */
:root {
  /* 色彩 */
  --ink: #060F1C;
  --ink-2: #0E1D33;
  --rock: #2A3A4D;
  --mist: #8FA3B8;
  --bone: #F2EDE3;
  --cyan: #35E0D0;
  --coral: #FF6B4A;
  --gold: #E8B45A;
  --moss: #4F7A5E;
  --clay: #B4643C;

  --cyan-soft: rgba(53, 224, 208, 0.12);
  --coral-soft: rgba(255, 107, 74, 0.12);
  --mist-line: rgba(143, 163, 184, 0.16);

  /* 字体 */
  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  /* 尺度 */
  --shell-max: 1280px;
  --gutter: clamp(20px, 5vw, 64px);
  --col-gap: 24px;
  --radius: 2px;

  /* 层级 */
  --z-nav: 190;
  --z-header: 200;
  --z-skip: 999;
}

/* ---------- 03. 中文排版基础 ---------- */
body {
  background-color: var(--ink);
  background-image:
    radial-gradient(1100px 560px at 88% -8%, rgba(53, 224, 208, 0.10), transparent 62%),
    radial-gradient(820px 460px at 2% 0%, rgba(255, 107, 74, 0.07), transparent 66%);
  background-repeat: no-repeat;
  color: var(--bone);
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.015em;
}

::selection { background: var(--cyan); color: #04141A; }

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

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 04. 布局骨架 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(56px, 8vw, 128px); }
.section--tight { padding-block: clamp(32px, 5vw, 72px); }

.section--bone {
  background: var(--bone);
  color: #0B1520;
}
.section--bone .lede { color: #4A5A6B; }
.section--bone .eyebrow { color: #1D6F68; }
.section--bone .divider { background: #C9C2B4; }

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--col-gap);
}
.grid > * { min-width: 0; }

.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-12 { grid-column: span 12; }

.divider {
  height: 1px;
  border: 0;
  background: var(--rock);
  margin-block: clamp(24px, 4vw, 48px);
}

/* ---------- 05. 文字组件 ---------- */
.display-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.5rem, 6vw, 6rem);
  line-height: 0.98;
  letter-spacing: -0.03em;
  margin-bottom: 0.5em;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
  text-transform: uppercase;
  margin-bottom: 20px;
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: currentColor;
  flex: none;
}

.lede {
  font-size: clamp(1.0625rem, 1.6vw, 1.25rem);
  line-height: 1.72;
  color: var(--mist);
  max-width: 46ch;
}

.prose {
  max-width: 68ch;
  font-size: 1.0625rem;
  line-height: 1.8;
}
.prose p { margin-bottom: 1.1em; }
.prose h2,
.prose h3 { margin: 1.8em 0 0.6em; }
.prose ul,
.prose ol { list-style: square; padding-left: 1.3em; margin-bottom: 1.2em; }
.prose li { margin-bottom: 0.4em; }
.prose a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 208, 0.4);
}
.prose a:hover { border-bottom-color: var(--cyan); }

.mono {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
}

.rail {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: var(--mist);
}
.rail__num { color: var(--cyan); }

/* ---------- 06. 按钮与链接 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 18px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  line-height: 1.2;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color 0.16s ease-out, color 0.16s ease-out,
              border-color 0.16s ease-out, transform 0.16s ease-out;
}

.btn--cta {
  background: var(--coral);
  color: #160B06;
  border-color: var(--coral);
}
.btn--cta:hover {
  background: #FF8768;
  border-color: #FF8768;
  transform: translateY(-1px);
}

.btn--ghost {
  background: transparent;
  color: var(--bone);
  border-color: var(--rock);
}
.btn--ghost:hover {
  color: var(--cyan);
  border-color: var(--cyan);
  transform: translateY(-1px);
}

.link-under {
  position: relative;
  color: var(--bone);
  text-decoration: none;
  transition: color 0.16s ease-out;
}
.link-under::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -3px;
  width: 100%;
  height: 1px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.18s ease-out;
}
.link-under:hover { color: var(--cyan); }
.link-under:hover::after,
.link-under:focus-visible::after { transform: scaleX(1); }

/* ---------- 07. 档案组件 ---------- */
.card {
  position: relative;
  background: linear-gradient(158deg, rgba(14, 29, 51, 0.94), rgba(6, 15, 28, 0.94));
  border: 1px solid var(--rock);
  border-radius: var(--radius);
  padding: clamp(20px, 3vw, 32px);
  transition: transform 0.18s ease-out, border-color 0.18s ease-out,
              box-shadow 0.18s ease-out;
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: 0 18px 40px -28px rgba(53, 224, 208, 0.65);
}
.card__idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
  margin-bottom: 14px;
}

.panel {
  background: rgba(14, 29, 51, 0.62);
  border: 1px solid var(--rock);
  border-radius: var(--radius);
  padding: clamp(20px, 3vw, 36px);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid currentColor;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  line-height: 1.6;
  color: var(--mist);
  text-transform: uppercase;
}
.tag--cyan { color: var(--cyan); }
.tag--coral { color: var(--coral); }
.tag--gold { color: var(--gold); }
.tag--moss { color: #7FB894; }

.index-list {
  border-top: 1px solid var(--rock);
}
.index-item {
  border-bottom: 1px solid var(--rock);
}
.index-item__link,
.index-item > a {
  display: grid;
  grid-template-columns: 3.5rem minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 4px 16px;
  padding: 18px 2px;
  color: var(--bone);
  text-decoration: none;
  transition: background-color 0.16s ease-out, color 0.16s ease-out,
              padding-left 0.16s ease-out;
}
.index-item__link:hover,
.index-item > a:hover {
  background: var(--cyan-soft);
  color: var(--cyan);
  padding-left: 10px;
}
.index-item__num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--cyan);
}
.index-item__text { font-weight: 500; }
.index-item__meta {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--mist);
}

/* ---------- 08. 图像容器基础 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--rock);
  border-radius: var(--radius);
  background:
    linear-gradient(150deg, #0E1D33 0%, #060F1C 72%),
    repeating-linear-gradient(0deg, var(--mist-line) 0 1px, transparent 1px 32px);
}
.media__img,
.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.media--wide { aspect-ratio: 16 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--cut {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 56px), 0 100%);
}
.media__scan {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    0deg,
    rgba(53, 224, 208, 0.08) 0 1px,
    transparent 1px 4px
  );
}

/* ---------- 09. 面包屑 ---------- */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--mist);
}
.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.breadcrumb__item { display: inline-flex; align-items: center; gap: 8px; }
.breadcrumb__link {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease-out, border-color 0.16s ease-out;
}
.breadcrumb__link:hover {
  color: var(--cyan);
  border-bottom-color: currentColor;
}
.breadcrumb__sep { color: var(--rock); }
.breadcrumb__current { color: var(--bone); }

/* ---------- 10. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: var(--z-skip);
  padding: 10px 16px;
  background: var(--cyan);
  color: #04141A;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  text-decoration: none;
  transform: translateY(-180%);
  transition: transform 0.18s ease-out;
}
.skip-link:focus,
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 11. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  --header-bar-h: 78px;
  --header-utility-h: 38px;
  --header-stack: calc(var(--header-bar-h) + var(--header-utility-h));
  color: var(--bone);
  background-color: rgba(6, 15, 28, 0.55);
  -webkit-backdrop-filter: blur(12px) saturate(130%);
  backdrop-filter: blur(12px) saturate(130%);
  border-bottom: 1px solid var(--mist-line);
  transition: background-color 0.2s ease-out, box-shadow 0.2s ease-out,
              border-color 0.2s ease-out;
}

.site-header[data-scrolled] {
  background-color: var(--ink);
  border-bottom-color: var(--rock);
  box-shadow: 0 18px 44px -34px #000;
}

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

/* 顶部信息带 */
.header-utility {
  border-bottom: 1px solid var(--mist-line);
}
.header-utility__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: var(--header-utility-h);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  color: var(--mist);
}
.header-utility__mark {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  white-space: nowrap;
}
.header-utility__mark::before {
  content: "";
  width: 6px;
  height: 6px;
  flex: none;
  background: var(--cyan);
  transform: rotate(45deg);
  box-shadow: 0 0 10px rgba(53, 224, 208, 0.8);
}
.header-utility__nav {
  display: flex;
  align-items: center;
  gap: 18px;
}
.header-utility__nav a {
  color: var(--mist);
  text-decoration: none;
  transition: color 0.16s ease-out;
}
.header-utility__nav a:hover { color: var(--cyan); }

/* 主控制条 */
.header-bar {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: var(--header-bar-h);
  transition: min-height 0.2s ease-out;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--bone);
  flex: none;
}
.brand__glyph {
  display: inline-flex;
  align-items: flex-end;
  justify-content: center;
  gap: 4px;
  width: 34px;
  height: 34px;
  padding: 7px;
  border: 1px solid rgba(53, 224, 208, 0.55);
  border-radius: var(--radius);
  transition: border-color 0.18s ease-out;
}
.brand__glyph i {
  display: block;
  width: 4px;
  background: var(--cyan);
  transition: height 0.18s ease-out, background-color 0.18s ease-out;
}
.brand__glyph i:first-child { height: 14px; }
.brand__glyph i:last-child { height: 8px; background: var(--coral); }
.brand:hover .brand__glyph { border-color: var(--cyan); }
.brand:hover .brand__glyph i:first-child { height: 8px; }
.brand:hover .brand__glyph i:last-child { height: 15px; }
.brand__text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  line-height: 1.15;
}
.brand__name {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 800;
  letter-spacing: 0.03em;
}
.brand__tag {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.14em;
  color: var(--mist);
  white-space: nowrap;
}

/* 主导航 */
.primary-nav { margin-left: auto; }
.primary-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}
.primary-nav__link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 10px 12px;
  color: var(--bone);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: color 0.16s ease-out, background-color 0.16s ease-out;
}
.primary-nav__idx {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.1em;
  color: var(--mist);
  transition: color 0.16s ease-out;
}
.primary-nav__link::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 1px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.18s ease-out, background-color 0.16s ease-out;
}
.primary-nav__link:hover { color: var(--cyan); }
.primary-nav__link:hover .primary-nav__idx { color: var(--cyan); }
.primary-nav__link:hover::after { transform: scaleX(1); }

.primary-nav__link[aria-current="page"] { color: var(--cyan); }
.primary-nav__link[aria-current="page"] .primary-nav__idx { color: var(--coral); }
.primary-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--coral);
}

/* 右侧动作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-left: clamp(10px, 1.6vw, 24px);
  flex: none;
}
.header-actions .btn {
  padding: 10px 15px;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
}

/* 移动菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  border: 1px solid var(--rock);
  border-radius: var(--radius);
  color: var(--bone);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  cursor: pointer;
  transition: color 0.16s ease-out, border-color 0.16s ease-out;
}
.nav-toggle:hover { color: var(--cyan); border-color: var(--cyan); }
.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 16px;
  height: 12px;
}
.nav-toggle__bars i {
  display: block;
  height: 1px;
  width: 100%;
  background: currentColor;
  transition: transform 0.18s ease-out, opacity 0.18s ease-out;
}
.nav-toggle__label { white-space: nowrap; }

.site-header[data-open] .nav-toggle {
  color: var(--coral);
  border-color: var(--coral);
}
.site-header[data-open] .nav-toggle__bars i:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}
.site-header[data-open] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.site-header[data-open] .nav-toggle__bars i:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

/* 阅读进度光轨 */
.header-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}
.header-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--cyan), var(--gold));
  opacity: 0;
  transition: opacity 0.2s ease-out;
}
.site-header[data-scrolled] .header-progress__bar { opacity: 1; }

/* ---------- 12. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 8vw, 96px);
  background-color: #050C16;
  background-image:
    repeating-linear-gradient(90deg, rgba(143, 163, 184, 0.055) 0 1px, transparent 1px 96px),
    radial-gradient(720px 340px at 10% 0%, rgba(53, 224, 208, 0.10), transparent 70%);
  background-repeat: no-repeat;
  color: var(--bone);
  border-top: 1px solid var(--rock);
  padding-top: clamp(48px, 7vw, 96px);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: min(420px, 42%);
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--coral));
}

.footer-inner {
  display: grid;
  grid-template-columns: minmax(260px, 5fr) 7fr;
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-lead__mark {
  display: inline-block;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3.4vw, 2.75rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--bone);
  text-decoration: none;
  transition: color 0.16s ease-out;
}
.footer-lead__mark:hover { color: var(--cyan); }
.footer-lead__sub {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
}
.footer-lead__note {
  margin: 16px 0 24px;
  max-width: 42ch;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--mist);
}

.footer-columns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: clamp(20px, 3vw, 40px);
}
.footer-col__title {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--mist);
  text-transform: uppercase;
}
.footer-col__title::before {
  content: "";
  width: 5px;
  height: 5px;
  flex: none;
  background: var(--gold);
  transform: rotate(45deg);
}
.footer-col__list li + li { margin-top: 12px; }
.footer-col__list .link-under {
  font-size: 0.9375rem;
  color: var(--bone);
}

.footer-contact {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: clamp(20px, 4vw, 56px);
  margin-top: clamp(28px, 4vw, 48px);
  padding-top: clamp(20px, 3vw, 28px);
  border-top: 1px solid var(--rock);
}
.footer-contact__row {
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 180px;
}
.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.16em;
  color: var(--mist);
  text-transform: uppercase;
}
.footer-contact__value {
  font-size: 0.9375rem;
  color: var(--bone);
  letter-spacing: 0.01em;
}

.footer-base {
  margin-top: clamp(28px, 4vw, 48px);
  border-top: 1px solid var(--mist-line);
}
.footer-base__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding: 20px var(--gutter);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--mist);
}
.footer-base__legal { color: var(--mist); }
.footer-base__addr { color: var(--mist); }

/* ---------- 13. 显现（可选页面级使用） ---------- */
html[data-motion="on"] .reveal {
  transition: opacity 0.4s ease-out, transform 0.4s ease-out;
}
html[data-motion="on"] .reveal:not(.is-visible) {
  opacity: 0;
  transform: translateY(14px);
}

/* ---------- 14. 响应式 ---------- */
@media (min-width: 1121px) {
  .site-header[data-scrolled] { --header-bar-h: 64px; }
}

@media (max-width: 1120px) {
  .site-header {
    --header-bar-h: 66px;
    --header-utility-h: 34px;
  }

  .header-bar { justify-content: space-between; }

  .brand__tag { display: none; }

  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: fixed;
    top: var(--header-stack);
    left: 0;
    right: 0;
    bottom: 0;
    z-index: var(--z-nav);
    margin-left: 0;
    padding: 24px var(--gutter) 48px;
    overflow-y: auto;
    overscroll-behavior: contain;
    background-color: var(--ink);
    background-image:
      repeating-linear-gradient(0deg, rgba(143, 163, 184, 0.06) 0 1px, transparent 1px 52px),
      radial-gradient(620px 320px at 84% 0%, rgba(53, 224, 208, 0.12), transparent 72%);
    background-repeat: no-repeat;
    border-top: 1px solid var(--rock);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.18s ease-out, transform 0.18s ease-out,
                visibility 0.18s linear;
  }

  .site-header[data-open] .primary-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .primary-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    border-top: 1px solid var(--rock);
  }
  .primary-nav__list li { border-bottom: 1px solid var(--rock); }
  .primary-nav__link {
    width: 100%;
    padding: 18px 4px;
    font-family: var(--font-display);
    font-size: 1.375rem;
    font-weight: 800;
    letter-spacing: 0.01em;
  }
  .primary-nav__idx {
    width: 34px;
    flex: none;
    font-size: 0.75rem;
    color: var(--cyan);
  }
  .primary-nav__link::after {
    left: 4px;
    right: 4px;
    bottom: 12px;
  }

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

@media (max-width: 900px) {
  body { font-size: 16px; }
  .span-4, .span-5, .span-6, .span-7, .span-8 { grid-column: span 12; }
}

@media (max-width: 720px) {
  .header-utility__inner {
    font-size: 0.625rem;
    letter-spacing: 0.12em;
  }
  .header-utility__mark { gap: 7px; }
  .header-utility__nav { gap: 12px; }
  .header-actions .btn {
    padding: 9px 12px;
    font-size: 0.6875rem;
    letter-spacing: 0.04em;
  }
  .nav-toggle__label { display: none; }
  .footer-lead__note { max-width: none; }
  .footer-contact__row { min-width: 140px; }
  .footer-base__inner { justify-content: flex-start; }
}

@media (max-width: 520px) {
  .header-actions .btn { display: none; }
  .footer-columns { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .footer-contact { flex-direction: column; gap: 18px; }
}

/* ---------- 15. 降低动态偏好 ---------- */
@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;
  }
  .btn:hover,
  .card:hover,
  .link-under:hover { transform: none; }
  html[data-motion="on"] .reveal:not(.is-visible) {
    opacity: 1;
    transform: none;
  }
}