/* ============================================================
   三亿体育看台 · /assets/site.css
   共享层：reset / 变量 / 中文排版 / 头部 / 页脚 / 基础组件
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

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 { display: block; max-width: 100%; }

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

a { color: inherit; }

button { background: none; border: 0; }

::selection {
  background: rgba(57, 242, 208, .28);
  color: #F5F1E8;
}

/* ---------- 2. 变量 ---------- */
:root {
  --c-indigo: #0B1026;
  --c-midnight: #111A3A;
  --c-stand: #1B2A5B;
  --c-cyan: #39F2D0;
  --c-orange: #FF6B35;
  --c-warm: #F5F1E8;
  --c-grey: #C9CEDC;
  --c-ink: #070912;
  --c-purple: #8B7BFF;
  --c-fog: #8FA3C8;

  --line: rgba(143, 163, 200, .24);
  --line-strong: rgba(143, 163, 200, .44);

  --radius-s: 10px;
  --radius-m: 18px;
  --radius-l: 32px;
  --radius-xl: 52px;

  --shell: 1200px;
  --gutter: clamp(16px, 4vw, 44px);

  --sp-1: 8px;
  --sp-2: 16px;
  --sp-3: 24px;
  --sp-4: 32px;
  --sp-5: 48px;
  --sp-6: 72px;
  --sp-7: 104px;

  --font-display: "Barlow Condensed", "DIN Condensed", "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "Roboto Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --shadow-1: 0 18px 40px -22px rgba(7, 9, 18, .9);
  --shadow-2: 0 30px 72px -30px rgba(7, 9, 18, .96);

  --ease: cubic-bezier(.22, .68, .32, 1);
  --dur: .24s;
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--c-warm);
  background-color: var(--c-indigo);
  background-image:
    radial-gradient(1100px 520px at 10% -10%, rgba(57, 242, 208, .10), transparent 62%),
    radial-gradient(960px 500px at 94% 2%, rgba(139, 123, 255, .13), transparent 60%),
    radial-gradient(820px 620px at 50% 108%, rgba(255, 107, 53, .07), transparent 66%);
  background-repeat: no-repeat;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: .01em;
  color: var(--c-warm);
}

p { line-height: 1.8; }

strong { font-weight: 700; }

:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: 3px;
  border-radius: 6px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -.01em;
}

.rule {
  height: 0;
  border: 0;
  border-top: 1px solid var(--line);
  background: none;
  margin-block: clamp(24px, 4vw, 44px);
}

/* ---------- 4. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 11px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
  line-height: 1.2;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition:
    transform .18s var(--ease),
    background-color .18s var(--ease),
    color .18s var(--ease),
    border-color .18s var(--ease),
    box-shadow .18s var(--ease);
}

.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn--signal {
  background: var(--c-orange);
  color: #1B0A03;
  box-shadow: 0 14px 30px -16px rgba(255, 107, 53, .95);
}
.btn--signal:hover { background: #FF8055; }

.btn--cyan {
  background: var(--c-cyan);
  color: #04231D;
  box-shadow: 0 14px 30px -18px rgba(57, 242, 208, .9);
}
.btn--cyan:hover { background: #5BF7DB; }

.btn--ghost {
  background: rgba(27, 42, 91, .45);
  color: var(--c-warm);
  border-color: var(--line-strong);
}
.btn--ghost:hover {
  border-color: var(--c-cyan);
  color: var(--c-cyan);
}

/* ---------- 5. 页头 ---------- */
.skip-link {
  position: fixed;
  top: 0;
  left: 50%;
  z-index: 200;
  transform: translate(-50%, -130%);
  padding: 12px 22px;
  border-radius: 0 0 14px 14px;
  background: var(--c-cyan);
  color: #04231D;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transition: transform .2s var(--ease);
}
.skip-link:focus-visible { transform: translate(-50%, 0); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background:
    linear-gradient(180deg, rgba(11, 16, 38, .99) 0%, rgba(11, 16, 38, .9) 100%);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
  transition: box-shadow var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.site-header[data-scrolled] {
  box-shadow: var(--shadow-2);
}

.site-header::after {
  content: "";
  display: block;
  height: 3px;
  background:
    linear-gradient(90deg,
      var(--c-cyan) 0 18%,
      var(--c-purple) 18% 33%,
      var(--c-orange) 33% 50%,
      rgba(143, 163, 200, .32) 50% 100%);
}

.tier__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(12px, 2vw, 28px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* 上层：节奏带 */
.tier--meta {
  background: rgba(7, 9, 18, .55);
  border-bottom: 1px solid var(--line);
}

.tier--meta .tier__inner {
  min-height: 42px;
  padding-block: 6px;
}

.tier__tag {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  line-height: 1.5;
  color: var(--c-fog);
}

.pulse-dot {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--c-cyan);
  box-shadow: 0 0 0 0 rgba(57, 242, 208, .55);
  animation: pulse 2.6s var(--ease) infinite;
}

@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(57, 242, 208, .5); }
  70% { box-shadow: 0 0 0 9px rgba(57, 242, 208, 0); }
  100% { box-shadow: 0 0 0 0 rgba(57, 242, 208, 0); }
}

.meta-nav {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 18px);
  font-size: 12px;
  letter-spacing: .05em;
  line-height: 1.5;
}

.meta-nav__link {
  color: var(--c-grey);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.meta-nav__link:hover { color: var(--c-cyan); border-color: currentColor; }

.meta-nav__link--accent {
  color: var(--c-orange);
  border-color: rgba(255, 107, 53, .45);
}
.meta-nav__link--accent:hover { color: #FF8055; }

.meta-nav__sep {
  width: 1px;
  height: 12px;
  background: var(--line-strong);
}

/* 下层：品牌 + 主栏目 */
.tier--primary .tier__inner {
  min-height: 76px;
  padding-block: 10px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--c-warm);
  flex: none;
}

.brand__mark {
  display: grid;
  place-items: center;
  flex: none;
  width: 52px;
  height: 52px;
  border-radius: 20px 8px 20px 8px;
  background: linear-gradient(150deg, #39F2D0 0%, #26D3B4 58%, #1F9F8D 100%);
  color: #04231D;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  letter-spacing: .02em;
  box-shadow: 0 12px 26px -14px rgba(57, 242, 208, .95);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 2vw, 21px);
  letter-spacing: .05em;
  color: var(--c-warm);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  color: var(--c-fog);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 8px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: rgba(27, 42, 91, .85);
  color: var(--c-warm);
  font-size: 13px;
  letter-spacing: .12em;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.nav-toggle:hover { border-color: var(--c-cyan); }

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 18px;
  height: 14px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--c-cyan);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.site-header[data-open] .nav-toggle__bars span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.site-header[data-open] .nav-toggle__bars span:nth-child(2) { opacity: 0; }
.site-header[data-open] .nav-toggle__bars span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(6px, 1.1vw, 18px);
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(4px, .9vw, 16px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__item { flex: none; }

.site-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  padding: 10px 6px;
  font-size: clamp(13px, 1.15vw, 15px);
  font-weight: 500;
  letter-spacing: .02em;
  color: var(--c-grey);
  text-decoration: none;
  white-space: nowrap;
  transition: color .18s var(--ease);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 6px;
  right: 6px;
  bottom: 3px;
  height: 2px;
  border-radius: 2px;
  background: var(--c-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur) var(--ease);
}

.site-nav__link:hover,
.site-nav__link:focus-visible { color: var(--c-warm); }
.site-nav__link:hover::after,
.site-nav__link:focus-visible::after { transform: scaleX(1); }

.site-nav__link[aria-current="page"] {
  color: var(--c-cyan);
  font-weight: 700;
}
.site-nav__link[aria-current="page"]::after { transform: scaleX(1); }

.site-nav__cta {
  flex: none;
  margin-inline-start: clamp(4px, 1vw, 14px);
  padding-inline: 18px;
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 8vw, 104px);
  overflow: hidden;
  border-top: 1px solid var(--line);
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  color: var(--c-grey);
  background:
    radial-gradient(900px 380px at 84% 0%, rgba(139, 123, 255, .15), transparent 62%),
    linear-gradient(180deg, #111A3A 0%, #0B1026 56%, #070912 100%);
}

.footer__stand {
  position: absolute;
  inset: 0 0 auto 0;
  height: 220px;
  pointer-events: none;
}

.footer__stand span {
  position: absolute;
  inset-inline: -12%;
  height: 150px;
  border-radius: 0 0 50% 50%;
  border-bottom: 1px solid rgba(143, 163, 200, .2);
}

.footer__stand span:nth-child(1) { top: -18px; opacity: .9; }
.footer__stand span:nth-child(2) { top: 14px; inset-inline: -6%; opacity: .6; }
.footer__stand span:nth-child(3) { top: 46px; inset-inline: 0; opacity: .35; }

.footer__inner {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.5fr) minmax(0, .95fr);
  gap: clamp(28px, 4vw, 56px);
  padding-block: clamp(44px, 6vw, 78px) clamp(30px, 4vw, 50px);
}

.footer__brandcol .btn { margin-top: 4px; }

.footer__brand {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 2.6vw, 30px);
  letter-spacing: .03em;
  line-height: 1.2;
  color: var(--c-warm);
}

.footer__tagline {
  margin: 0 0 18px;
  max-width: 22em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--c-fog);
}

.footer__hours {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 22px;
  padding: 6px 14px;
  border: 1px solid rgba(57, 242, 208, .32);
  border-radius: 999px;
  background: rgba(57, 242, 208, .07);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--c-cyan);
}

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

.footer__group { min-width: 0; }

.footer__group-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .2em;
  line-height: 1.6;
  color: var(--c-purple);
}

.footer__list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer__link {
  display: inline-block;
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-grey);
  text-decoration: none;
  transition: color .18s var(--ease), transform .18s var(--ease);
}
.footer__link:hover {
  color: var(--c-warm);
  transform: translateX(3px);
}

.footer__contact { min-width: 0; }

.footer__label {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .2em;
  line-height: 1.6;
  color: var(--c-purple);
}

.footer__line {
  margin: 0 0 6px;
  font-size: 13px;
  line-height: 1.9;
  color: var(--c-grey);
  word-break: break-word;
}

.footer__contact .footer__link {
  margin-top: 10px;
  color: var(--c-cyan);
}

.footer__base {
  position: relative;
  border-top: 1px solid var(--line);
  background: rgba(7, 9, 18, .62);
}

.footer__base-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 24px;
  padding-block: 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--c-fog);
}

.footer__copy,
.footer__icp,
.footer__region { margin: 0; }

/* ---------- 7. 通用内容组件 ---------- */
.page-head {
  padding-block: clamp(26px, 4vw, 48px) clamp(18px, 3vw, 32px);
}

.kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .24em;
  line-height: 1.6;
  color: var(--c-purple);
}
.kicker::before {
  content: "";
  width: 22px;
  height: 1px;
  background: currentColor;
}

.display {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.2vw, 58px);
  line-height: 1.08;
  letter-spacing: .01em;
  color: var(--c-warm);
}

.lede {
  max-width: 34em;
  margin: 0;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--c-grey);
}

.section { padding-block: clamp(36px, 5.5vw, 80px); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 24px;
  margin-bottom: clamp(20px, 3vw, 36px);
}

.section__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 3.2vw, 36px);
  line-height: 1.2;
  color: var(--c-warm);
}

.band {
  position: relative;
  padding-block: clamp(24px, 4vw, 44px);
  border-block: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(27, 42, 91, .58), rgba(17, 26, 58, .22) 72%, transparent);
}

.grid {
  display: grid;
  gap: clamp(18px, 2.4vw, 32px);
}

.grid--split {
  grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
  align-items: start;
}

.grid--auto {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
}

.prose {
  max-width: 36em;
  font-size: 17px;
  line-height: 1.85;
  color: rgba(245, 241, 232, .86);
}

.prose > * + * { margin-top: 1.05em; }

.prose h2 {
  margin-top: 1.9em;
  font-size: clamp(20px, 2.4vw, 26px);
  line-height: 1.35;
  font-weight: 800;
  color: var(--c-warm);
}

.prose h3 {
  margin-top: 1.6em;
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.5;
  font-weight: 700;
  color: var(--c-warm);
}

.prose ul,
.prose ol {
  padding-left: 1.15em;
  list-style: revert;
}

.prose li + li { margin-top: .4em; }
.prose li::marker { color: var(--c-cyan); }

.prose a {
  color: var(--c-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.prose strong { color: var(--c-warm); font-weight: 700; }

.prose mark {
  padding: 0 .22em;
  border-radius: 4px;
  background: rgba(255, 107, 53, .22);
  color: var(--c-warm);
}

.prose code {
  padding: .12em .42em;
  border-radius: 6px;
  background: rgba(27, 42, 91, .8);
  font-family: var(--font-mono);
  font-size: .92em;
  color: var(--c-cyan);
}

.callout {
  padding: 16px 20px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--c-cyan);
  border-radius: 0 var(--radius-m) var(--radius-m) 0;
  background: rgba(27, 42, 91, .55);
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-grey);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  border: 1px solid rgba(139, 123, 255, .45);
  border-radius: 999px;
  background: rgba(139, 123, 255, .12);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  line-height: 1.5;
  color: #C6BFFF;
}

.tag--cyan {
  border-color: rgba(57, 242, 208, .42);
  background: rgba(57, 242, 208, .1);
  color: var(--c-cyan);
}

/* 图片槽位：页面阶段直接放 img */
.media-frame {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  background: linear-gradient(150deg, var(--c-stand) 0%, var(--c-midnight) 58%, #0B1026 100%);
}

.media-frame img,
.media-frame picture,
.media-frame video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, rgba(11, 16, 38, 0) 42%, rgba(7, 9, 18, .58) 100%);
  pointer-events: none;
}

.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall {
  aspect-ratio: 3 / 4;
  border-radius: var(--radius-xl) var(--radius-l) var(--radius-xl) var(--radius-l);
}

.media-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  line-height: 1.7;
  color: var(--c-fog);
}

/* 面包屑 */
.breadcrumbs { padding-block: 16px 0; }

.breadcrumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--c-fog);
}

.breadcrumbs__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumbs__item[aria-current="page"] { color: var(--c-warm); }

.breadcrumbs__link {
  color: var(--c-fog);
  text-decoration: none;
  transition: color .18s var(--ease);
}
.breadcrumbs__link:hover { color: var(--c-cyan); }

.breadcrumbs__sep { color: rgba(143, 163, 200, .5); }

/* ---------- 8. 脚本注入件与显现态 ---------- */
.progress-rail {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 120;
  height: 3px;
  background: rgba(143, 163, 200, .12);
  pointer-events: none;
}

.progress-rail__bar {
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--c-cyan), var(--c-orange));
  transition: transform .1s linear;
}

.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .32s var(--ease), transform .32s var(--ease);
}

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

/* ---------- 9. 响应式 ---------- */
@media (max-width: 1040px) {
  .footer__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }
  .footer__contact { grid-column: 1 / -1; }
  .site-nav__cta { padding-inline: 14px; }
}

@media (max-width: 900px) {
  html { scroll-padding-top: 120px; }

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

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 5;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-height: calc(100vh - 110px);
    padding: 10px var(--gutter) 24px;
    overflow-y: auto;
    border-bottom: 1px solid var(--line-strong);
    background: linear-gradient(180deg, #111A3A 0%, #0B1026 100%);
    box-shadow: 0 28px 54px -24px rgba(7, 9, 18, .95);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity .22s var(--ease), transform .22s var(--ease), visibility .22s linear;
  }

  .site-header[data-open] .site-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__item { width: 100%; }

  .site-nav__link {
    display: block;
    padding: 15px 4px;
    font-size: 17px;
    border-bottom: 1px solid var(--line);
  }

  .site-nav__link::after {
    left: 0;
    right: auto;
    bottom: 10px;
    width: 26px;
  }

  .site-nav__link[aria-current="page"]::after { transform: scaleX(1); }

  .site-nav__cta {
    justify-content: center;
    width: 100%;
    margin: 20px 0 0;
    min-height: 48px;
  }

  .tier--primary .tier__inner { min-height: 68px; }
  .brand__mark { width: 46px; height: 46px; border-radius: 18px 7px 18px 7px; font-size: 16px; }

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

  .page-head { padding-block: 22px 26px; }
}

@media (max-width: 720px) {
  .tier--meta .tier__inner {
    flex-wrap: wrap;
    gap: 4px 14px;
    padding-block: 8px;
  }

  .tier__tag { font-size: 11px; }
  .meta-nav { font-size: 11px; gap: 10px; }

  .footer__inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
    padding-block: 40px 32px;
  }

  .site-footer { border-radius: 36px 36px 0 0; }

  .footer__base-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }
}

@media (max-width: 560px) {
  .brand__sub { display: none; }
  .footer__links { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .prose { font-size: 16px; }
  .footer__tagline { max-width: none; }
}

/* ---------- 10. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  .pulse-dot { animation: none; }

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

  .btn:hover,
  .footer__link:hover { transform: none; }
}