/* ============================================================
   冠竞赛场 · 共享样式 /assets/site.css
   夜场赛场控制台：墨绿基底 + 荧光青数据线 + 赛道橙斜切
   ============================================================ */

/* ---------- 1. 变量 ---------- */
:root {
  --ink: #0A1613;
  --panel: #10241E;
  --panel-up: #17332B;
  --line: #245045;
  --text: #E9F5F0;
  --muted: #9FBDB2;
  --cyan: #22F0C4;
  --orange: #FF6B33;
  --signal: #FFD64A;
  --paper: #F2EFE3;
  --paper-ink: #0E1E19;
  --sage: #6E8F84;

  --font-display: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --header-h: 84px;
  --max: 1320px;
  --slant: -6deg;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

@media (max-width: 1080px) {
  :root { --header-h: 68px; }
}

/* ---------- 2. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
}

body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(130% 70% at 82% -12%, rgba(23, 51, 43, .92), transparent 62%),
    radial-gradient(90% 60% at -10% 100%, rgba(255, 107, 51, .06), transparent 60%),
    var(--ink);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg, video { display: block; max-width: 100%; }
h1, h2, h3, h4, p, ul, ol, figure, blockquote, dl { margin: 0; }
ul, ol { padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; }

::selection { background: var(--cyan); color: #04120E; }

:where(a, button, [tabindex]):focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 2px;
}

#main-content { padding-top: var(--header-h); }

/* ---------- 3. 排版 ---------- */
h1, h2 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--text);
}
h1 { font-size: clamp(2.2rem, 5vw, 5.5rem); }
h2 { font-size: clamp(1.7rem, 3.2vw, 2.8rem); }
h3 {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: clamp(1.1rem, 1.6vw, 1.45rem);
  line-height: 1.35;
  letter-spacing: 0.02em;
  color: var(--text);
}
strong { color: var(--text); font-weight: 700; }

/* ---------- 4. 通用结构 ---------- */
.container {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 48px);
}

.section { position: relative; padding-block: clamp(56px, 7vw, 104px); }

.panel {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: clamp(24px, 4vw, 48px);
  box-shadow: 0 1px 0 rgba(255, 255, 255, .02);
}
.panel--raised { background: var(--panel-up); }
.panel--paper {
  background: var(--paper);
  color: var(--paper-ink);
  border-color: #D8D3C2;
}
.panel--paper h2, .panel--paper h3, .panel--paper strong { color: var(--paper-ink); }
.panel--paper .eyebrow { color: #6B6250; }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 14px 24px;
  margin-bottom: clamp(24px, 3vw, 40px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--sage);
}
.eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--orange);
  flex: 0 0 auto;
}

.section-index {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(56px, 9vw, 96px);
  line-height: 0.8;
  letter-spacing: -0.04em;
  color: var(--orange);
}

.rule {
  height: 1px;
  border: 0;
  background: var(--line);
  margin-block: clamp(28px, 4vw, 48px);
}

/* ---------- 5. 网格 ---------- */
.grid { display: grid; gap: clamp(20px, 3vw, 40px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--5-7 { grid-template-columns: 5fr 7fr; }
.grid--7-5 { grid-template-columns: 7fr 5fr; }

@media (max-width: 900px) {
  .grid--2, .grid--3, .grid--5-7, .grid--7-5 { grid-template-columns: 1fr; }
}

/* ---------- 6. 按钮与链接 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 22px;
  border: 1px solid var(--line);
  border-radius: 2px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.2;
  text-align: center;
  transition: background-color 180ms var(--ease), color 180ms var(--ease),
              border-color 180ms var(--ease), transform 180ms var(--ease),
              box-shadow 180ms var(--ease);
}
.btn--solid {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #04120E;
}
.btn--solid:hover, .btn--solid:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 0 0 3px rgba(34, 240, 196, .18);
}
.btn--ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--text);
}
.btn--ghost:hover, .btn--ghost:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}
.btn--orange {
  background: var(--orange);
  border-color: var(--orange);
  color: #1A0A02;
}

.link-more {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--cyan);
  border-bottom: 1px solid rgba(34, 240, 196, .35);
  padding-bottom: 2px;
}
.link-more::after {
  content: "→";
  font-family: var(--font-mono);
  transition: transform 180ms var(--ease);
}
.link-more:hover::after { transform: translateX(4px); }

.link-list { display: grid; border-top: 1px solid var(--line); }
.link-list li { border-bottom: 1px solid var(--line); }
.link-list a {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 16px 0 16px 14px;
  color: var(--text);
  transition: color 180ms var(--ease);
}
.link-list a::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: var(--orange);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 180ms var(--ease);
}
.link-list a:hover { color: var(--cyan); }
.link-list a:hover::before { transform: scaleY(1); }

/* ---------- 7. 数据组件 ---------- */
.data-bar {
  --fill: 60%;
  position: relative;
  height: 6px;
  background: rgba(34, 240, 196, .14);
  overflow: hidden;
  border-radius: 1px;
}
.data-bar::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--fill);
  background: var(--cyan);
}

.metric {
  display: grid;
  gap: 6px;
  padding: 18px 20px;
  background: var(--panel-up);
  border: 1px solid var(--line);
  border-radius: 3px;
}
.metric-value {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--signal);
  font-variant-numeric: tabular-nums;
}
.metric-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--sage);
}

.scorecard {
  display: grid;
  gap: 12px;
  padding: 18px 20px;
  background: var(--panel-up);
  border: 1px solid var(--line);
  border-radius: 3px;
  transition: transform 200ms var(--ease), border-color 200ms var(--ease),
              box-shadow 200ms var(--ease);
}
.scorecard:hover {
  transform: translateY(-2px);
  border-color: var(--cyan);
  box-shadow: 0 14px 26px -20px rgba(34, 240, 196, .85);
}
.scorecard-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--sage);
}
.scorecard-teams {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}
.scorecard-team { font-weight: 700; font-size: 0.95rem; line-height: 1.3; }
.score-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.65rem;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--signal);
  font-variant-numeric: tabular-nums;
}
.scorecard-meta { font-size: 0.8rem; color: var(--muted); }

.tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border: 1px solid rgba(34, 240, 196, .35);
  border-radius: 2px;
  background: rgba(34, 240, 196, .07);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
}
.tag--orange {
  border-color: rgba(255, 107, 51, .4);
  background: rgba(255, 107, 51, .09);
  color: var(--orange);
}

/* ---------- 8. 正文与面包屑 ---------- */
.prose {
  max-width: 38em;
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--muted);
}
.prose p + p { margin-top: 1em; }
.prose h2, .prose h3 { margin-top: 1.6em; margin-bottom: .5em; color: var(--text); }
.prose ul, .prose ol { margin-top: .8em; }
.prose li { position: relative; padding-left: 20px; margin-top: .5em; }
.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 10px;
  height: 2px;
  background: var(--orange);
}
.prose a { color: var(--cyan); border-bottom: 1px solid rgba(34, 240, 196, .4); }

.breadcrumbs { padding-block: 20px 8px; }
.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--sage);
}
.breadcrumbs li:not(:last-child)::after {
  content: "/";
  margin-left: 8px;
  color: var(--line);
}
.breadcrumbs a { color: var(--muted); }
.breadcrumbs a:hover { color: var(--cyan); }
.breadcrumbs [aria-current="page"] { color: var(--text); }

/* ---------- 9. 首屏与装饰 ---------- */
.slab-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  margin-top: calc(-1 * var(--header-h));
  padding-top: calc(var(--header-h) + clamp(48px, 8vw, 96px));
  padding-bottom: clamp(56px, 8vw, 110px);
}
.slab-hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -20%;
  right: -14%;
  width: min(760px, 74vw);
  height: 130%;
  background: linear-gradient(160deg, rgba(23, 51, 43, .96), rgba(16, 36, 30, .3));
  transform: skewY(var(--slant));
}
.slab-hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  bottom: -32%;
  left: -18%;
  width: min(560px, 62vw);
  height: 92%;
  background: linear-gradient(160deg, rgba(255, 107, 51, .18), transparent 72%);
  transform: skewY(var(--slant));
}

.slant-band {
  position: relative;
  overflow: hidden;
  border-block: 1px solid var(--line);
  background: var(--panel);
}
.slant-band::before {
  content: "";
  position: absolute;
  inset: -12% -6%;
  background: repeating-linear-gradient(
    90deg,
    rgba(34, 240, 196, .07) 0 2px,
    transparent 2px 88px
  );
  transform: skewY(var(--slant));
  pointer-events: none;
}

/* ---------- 10. 图片容器 ---------- */
.img-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--line);
  border-radius: 3px;
  background:
    radial-gradient(120% 90% at 15% 8%, rgba(34, 240, 196, .18), transparent 58%),
    radial-gradient(90% 80% at 86% 92%, rgba(255, 107, 51, .16), transparent 60%),
    linear-gradient(160deg, #0E1F1A 0%, #10241E 56%, #0A1613 100%);
}
.img-frame::before {
  content: "";
  position: absolute;
  top: -24%;
  right: -12%;
  width: 46%;
  height: 148%;
  background: linear-gradient(180deg, rgba(34, 240, 196, .16), transparent 72%);
  transform: skewY(var(--slant));
  pointer-events: none;
}
.img-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 56%, rgba(10, 22, 19, .74));
  pointer-events: none;
}
.img-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.img-frame--4x3 { aspect-ratio: 4 / 3; }
.img-frame--1x1 { aspect-ratio: 1 / 1; }
.img-frame--21x9 { aspect-ratio: 21 / 9; }

.figure-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--sage);
}

/* ---------- 11. 章节目录 ---------- */
.toc { position: sticky; top: calc(var(--header-h) + 24px); }
.toc-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--sage);
  margin-bottom: 14px;
}
.toc-list { display: grid; gap: 2px; border-left: 1px solid var(--line); }
.toc-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-left: -1px;
  padding: 9px 0 9px 14px;
  border-left: 2px solid transparent;
  font-size: 0.9rem;
  color: var(--muted);
  white-space: nowrap;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}
.toc-link:hover { color: var(--text); }
.toc-link[aria-current="true"] {
  color: var(--cyan);
  border-left-color: var(--cyan);
}

@media (max-width: 1080px) {
  .toc { position: static; margin-bottom: 24px; }
  .toc-list {
    display: flex;
    gap: 0;
    overflow-x: auto;
    border-left: 0;
    border-bottom: 1px solid var(--line);
    -webkit-overflow-scrolling: touch;
  }
  .toc-link {
    margin-left: 0;
    border-left: 0;
    border-bottom: 2px solid transparent;
    padding: 10px 16px;
  }
  .toc-link[aria-current="true"] { border-bottom-color: var(--cyan); }
}

/* ---------- 12. 页头 ---------- */
.skip-link {
  position: fixed;
  top: -100px;
  left: 16px;
  z-index: 200;
  padding: 12px 18px;
  background: var(--cyan);
  color: #04120E;
  font-weight: 700;
  border-radius: 2px;
  transition: top 180ms var(--ease);
}
.skip-link:focus-visible { top: 16px; }

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 90;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color 240ms var(--ease), border-color 240ms var(--ease),
              height 240ms var(--ease), backdrop-filter 240ms var(--ease);
}
.site-header.is-stuck {
  --header-h: 64px;
  background: rgba(10, 22, 19, .97);
  border-bottom-color: var(--line);
  backdrop-filter: blur(8px);
}
.site-header[data-nav-open="true"] {
  background: rgba(10, 22, 19, .98);
  border-bottom-color: var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  height: 100%;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 0 0 auto;
  line-height: 1;
}
.brand-cn {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.32rem;
  letter-spacing: 0.16em;
  color: var(--text);
}
.brand-latin {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--muted);
  transition: opacity 200ms var(--ease), transform 200ms var(--ease);
}
.site-header.is-stuck .brand-latin {
  opacity: 0;
  transform: translateY(-6px);
}
.brand:hover .brand-cn { color: var(--cyan); }

.nav-toggle {
  display: none;
  margin-left: auto;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 2px;
  color: var(--text);
  transition: border-color 180ms var(--ease), color 180ms var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); color: var(--cyan); }
.nav-toggle-label {
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}
.nav-toggle-icon {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: background-color 160ms var(--ease);
}
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: transform 200ms var(--ease), top 200ms var(--ease);
}
.nav-toggle-icon::before { top: -6px; }
.nav-toggle-icon::after { top: 6px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before { top: 0; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after { top: 0; transform: rotate(-45deg); }

.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: clamp(16px, 2vw, 34px);
  flex: 1 1 auto;
  margin-left: auto;
}
.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(12px, 1.7vw, 24px);
}
.nav-item { flex: 0 0 auto; }
.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 10px 2px;
  font-size: 0.94rem;
  color: var(--text);
  white-space: nowrap;
  transition: color 180ms var(--ease);
}
.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  color: var(--sage);
  transition: color 180ms var(--ease);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 2px;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 200ms var(--ease);
}
.nav-link:hover { color: var(--cyan); }
.nav-link:hover .nav-index { color: var(--orange); }
.nav-link:hover::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: var(--cyan); }
.nav-link[aria-current="page"] .nav-index { color: var(--orange); }
.nav-link[aria-current="page"]::after { transform: scaleX(1); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: 0 0 auto;
}
.nav-actions .btn { padding: 10px 18px; font-size: 0.85rem; }
.nav-quick {
  font-size: 0.82rem;
  color: var(--muted);
  padding-bottom: 2px;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}
.nav-quick:hover { color: var(--cyan); border-color: var(--cyan); }

.header-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  overflow: hidden;
  background: transparent;
}
.header-progress span {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--cyan), var(--signal));
}

/* ---------- 13. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--panel);
  border-top: 1px solid var(--line);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(280px, 46%);
  height: 3px;
  background: var(--cyan);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.45fr 1fr 1fr 1.25fr;
  gap: clamp(24px, 3vw, 48px);
  padding-block: clamp(44px, 6vw, 76px) clamp(32px, 4vw, 48px);
}
.footer-brand { display: flex; flex-direction: column; align-items: flex-start; }
.brand--footer { margin-bottom: 16px; }
.footer-note {
  max-width: 32ch;
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--muted);
}
.footer-motto {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--orange);
}
.footer-title {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--sage);
  margin-bottom: 16px;
}
.footer-list { display: grid; gap: 10px; }
.footer-list a {
  font-size: 0.92rem;
  color: var(--muted);
  transition: color 180ms var(--ease);
}
.footer-list a:hover { color: var(--cyan); }
.footer-meta li {
  display: grid;
  gap: 2px;
  font-size: 0.86rem;
  line-height: 1.6;
  color: var(--muted);
  word-break: break-word;
}
.footer-meta-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--sage);
}

.footer-bottom { border-top: 1px solid var(--line); }
.footer-bottom-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-block: 18px 26px;
  font-size: 0.8rem;
  color: var(--sage);
}
.footer-legal { display: flex; flex-wrap: wrap; gap: 8px 20px; }
.footer-legal a { color: var(--muted); transition: color 180ms var(--ease); }
.footer-legal a:hover { color: var(--cyan); }
.footer-icp { font-family: var(--font-mono); letter-spacing: 0.06em; }

/* ---------- 14. 返回顶部 ---------- */
.to-top {
  position: fixed;
  right: clamp(16px, 3vw, 32px);
  bottom: clamp(16px, 3vw, 32px);
  z-index: 80;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: var(--panel-up);
  color: var(--cyan);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 200ms var(--ease), transform 200ms var(--ease),
              border-color 200ms var(--ease), visibility 0ms linear 200ms;
}
.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition: opacity 200ms var(--ease), transform 200ms var(--ease),
              border-color 200ms var(--ease);
}
.to-top:hover { border-color: var(--cyan); background: var(--panel); }
.to-top-icon {
  font-family: var(--font-mono);
  font-size: 1rem;
  line-height: 1;
}

/* ---------- 15. 显现动效 ---------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 480ms ease-out, transform 480ms ease-out;
}
.js [data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}

/* ---------- 16. 响应式 ---------- */
@media (max-width: 1080px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    margin-left: 0;
    padding: 8px clamp(20px, 4vw, 48px) 28px;
    background: rgba(10, 22, 19, .985);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 28px 44px -32px #000;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 220ms var(--ease), transform 220ms var(--ease),
                visibility 0ms linear 220ms;
  }
  .site-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: opacity 220ms var(--ease), transform 220ms var(--ease);
  }

  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-item { border-bottom: 1px solid var(--line); }
  .nav-link { width: 100%; padding: 16px 0; font-size: 1.05rem; }
  .nav-link::after { display: none; }
  .nav-link[aria-current="page"] { color: var(--cyan); }

  .nav-actions {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    margin-top: 22px;
  }
  .nav-actions .btn { width: 100%; padding: 13px 18px; font-size: 0.92rem; }
  .nav-quick { align-self: flex-start; font-size: 0.86rem; }

  .footer-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 700px) {
  .footer-inner { grid-template-columns: 1fr; gap: 32px; }
  .footer-bottom-inner { justify-content: flex-start; }
  .brand-cn { font-size: 1.18rem; }
}

/* ---------- 17. 无障碍动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  .js [data-reveal] { opacity: 1; transform: none; }
  .site-nav { transition: none; }
}