/* ==========================================================================
   乐游赛场 · 共享样式表 /assets/site.css
   夜间赛场 · 数据脉冲 —— reset → 变量 → 排版 → 组件 → 页头 → 页脚 → 响应式
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 104px;
}
body, h1, h2, h3, h4, h5, p, figure, blockquote, dl, dd, ol, ul { margin: 0; }
ol, ul { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; border-top: 1px solid var(--line); margin: 0; }

/* ---------- 2. 变量 ---------- */
:root {
  --night: #070E1C;
  --void: #0C1830;
  --board: #14243E;
  --cyan: #2FE3CE;
  --cyan-deep: #1BA795;
  --flare: #FF5A36;
  --silver: #EAF0F8;
  --mist: #8FA3BF;
  --line: #22334F;
  --paper: #F1F5FA;
  --ink: #0C1830;

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

  --shell: 1200px;
  --gutter: clamp(18px, 4vw, 44px);
  --header-h: 76px;
  --radius: 2px;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --t-fast: 200ms;
  --t-mid: 320ms;
  --t-slow: 420ms;
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  overflow-x: hidden;
  background-color: var(--void);
  background-image:
    repeating-linear-gradient(90deg, rgba(34, 51, 79, .5) 0 1px, transparent 1px 92px),
    radial-gradient(880px 540px at 84% -12%, rgba(47, 227, 206, .10), transparent 62%),
    radial-gradient(640px 460px at -8% 102%, rgba(255, 90, 54, .07), transparent 58%),
    linear-gradient(180deg, #070E1C 0%, #0C1830 46%, #091120 100%);
  color: var(--silver);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
}
h1, h2 { font-family: var(--font-display); font-weight: 700; line-height: 1.2; }
h3, h4, h5 { font-family: var(--font-sans); font-weight: 800; line-height: 1.3; }
h1 { font-size: clamp(30px, 4.6vw, 54px); }
h2 { font-size: clamp(23px, 3vw, 34px); }
h3 { font-size: 19px; }
p { max-width: 76ch; }
::selection { background: var(--cyan); color: #04121A; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; border-radius: 2px; }

/* ---------- 4. 容器与通用 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.page-top { padding-top: calc(var(--header-h) + clamp(26px, 5vw, 66px)); }
.kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--cyan);
}
.kicker::before { content: ""; width: 26px; height: 1px; background: var(--cyan); }
.grid { display: grid; gap: clamp(16px, 2.4vw, 28px); }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(238px, 1fr)); }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

/* 编号章节 */
.sec-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(14px, 2.6vw, 30px);
  align-items: start;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
  margin-bottom: clamp(20px, 3vw, 34px);
}
.sec-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(30px, 4.4vw, 54px);
  line-height: .92;
  letter-spacing: -.02em;
  color: var(--cyan);
}
@supports (-webkit-text-stroke: 1px currentColor) {
  .sec-num { color: transparent; -webkit-text-stroke: 1px rgba(47, 227, 206, .62); }
}
.sec-title { font-family: var(--font-display); font-weight: 700; font-size: clamp(22px, 2.8vw, 32px); }
.sec-sub {
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}
.sec-body { margin-top: 14px; font-size: 16px; line-height: 1.8; color: #C3D0E2; }

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 26px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .04em;
  text-align: center;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}
.btn--primary { background: var(--cyan); color: #04121A; border-color: var(--cyan); }
.btn--primary:hover { background: #57F0DE; border-color: #57F0DE; transform: translateY(-2px); }
.btn--flare { background: var(--flare); color: #1A0600; border-color: var(--flare); }
.btn--flare:hover { background: #FF7A5C; border-color: #FF7A5C; transform: translateY(-2px); }
.btn--ghost { background: rgba(47, 227, 206, .05); border-color: var(--line); color: var(--silver); }
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); transform: translateY(-2px); }
.btn--sm { padding: 9px 16px; font-size: 13px; }

/* ---------- 6. 数据与卡片组件 ---------- */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.stat { background: rgba(12, 24, 48, .88); padding: clamp(14px, 2vw, 22px); }
.stat-val {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1.1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}
.stat-key { margin-top: 6px; font-size: 12.5px; letter-spacing: .06em; color: var(--mist); }

.meter-bar {
  position: relative;
  height: 6px;
  border-radius: 1px;
  background: rgba(34, 51, 79, .75);
  overflow: hidden;
}
.meter-fill {
  display: block;
  height: 100%;
  width: var(--v, 0%);
  background: linear-gradient(90deg, var(--cyan), var(--cyan-deep));
  transition: width var(--t-slow) var(--ease);
}
.meter-fill--flare { background: linear-gradient(90deg, var(--flare), #B23A1E); }

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(18px, 2.4vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(20, 36, 62, .82), rgba(12, 24, 48, .86));
  transition: border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}
.card:hover { border-color: rgba(47, 227, 206, .5); transform: translateY(-3px); }
.card-title { font-family: var(--font-sans); font-weight: 800; font-size: 19px; line-height: 1.35; color: var(--silver); }
.card-meta { font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .1em; color: var(--mist); }
.card-body { font-size: 15px; line-height: 1.72; color: #C3D0E2; }

.panel {
  padding: clamp(18px, 2.6vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(12, 24, 48, .62);
}

.tag {
  display: inline-block;
  padding: 4px 9px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--mist);
}
.tag--data { color: var(--cyan); border-color: rgba(47, 227, 206, .45); background: rgba(47, 227, 206, .08); }
.tag--live { color: var(--flare); border-color: rgba(255, 90, 54, .5); background: rgba(255, 90, 54, .1); }

/* ---------- 7. 标签页 / 折叠面板 / 目录 ---------- */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-bottom: 12px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--line);
}
.tab {
  padding: 9px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 700;
  color: var(--mist);
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease);
}
.tab:hover { color: var(--silver); border-color: rgba(47, 227, 206, .45); }
.tab[aria-selected="true"] { background: var(--cyan); border-color: var(--cyan); color: #04121A; }
.tab-panel[hidden] { display: none; }

.acc-item {
  margin-bottom: 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(12, 24, 48, .58);
  overflow: hidden;
}
.acc-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 16px 18px;
  text-align: left;
  font-size: 16px;
  font-weight: 700;
  color: var(--silver);
}
.acc-trigger::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--cyan);
  transition: transform var(--t-fast) var(--ease);
}
.acc-trigger[aria-expanded="true"]::after { content: "–"; }
.acc-panel { padding: 0 18px 18px; font-size: 15.5px; line-height: 1.8; color: var(--mist); }
.acc-panel[hidden] { display: none; }

.toc { border-left: 1px solid var(--line); padding-left: 16px; }
.toc-title {
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--mist);
}
.toc-list { display: flex; flex-direction: column; gap: 2px; }
.toc-link {
  display: block;
  margin-left: -18px;
  padding: 7px 0 7px 12px;
  border-left: 2px solid transparent;
  font-size: 14.5px;
  color: var(--mist);
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.toc-link:hover { color: var(--silver); }
.toc-link[aria-current] { color: var(--cyan); border-left-color: var(--cyan); }

/* ---------- 8. 面包屑 / 正文 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--mist);
}
.breadcrumb li { display: flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: "/"; color: var(--line); }
.breadcrumb a { color: var(--mist); }
.breadcrumb a:hover { color: var(--cyan); }

.prose { max-width: 74ch; font-size: 17px; line-height: 1.85; color: #CFDAEA; }
.prose > * + * { margin-top: 1.1em; }
.prose h2 { margin-top: 1.9em; font-family: var(--font-display); font-weight: 700; font-size: clamp(21px, 2.6vw, 28px); color: var(--silver); }
.prose h3 { margin-top: 1.6em; font-size: 18px; color: var(--silver); }
.prose ul, .prose ol { list-style: disc; padding-left: 1.35em; }
.prose ol { list-style: decimal; }
.prose li + li { margin-top: .4em; }
.prose a { color: var(--cyan); border-bottom: 1px solid rgba(47, 227, 206, .35); }
.prose a:hover { border-bottom-color: var(--cyan); }
.prose strong { color: var(--silver); }
.prose blockquote { border-left: 2px solid var(--cyan); padding: 2px 0 2px 18px; color: var(--mist); }
.prose code {
  font-family: var(--font-mono);
  font-size: .92em;
  padding: 2px 6px;
  border-radius: 2px;
  background: rgba(34, 51, 79, .6);
}
.prose table { margin-top: 1.4em; font-size: 15px; }
.prose th, .prose td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--line); }
.prose th { font-family: var(--font-mono); font-size: 12px; letter-spacing: .1em; font-weight: 500; color: var(--mist); }
.prose--paper {
  max-width: 84ch;
  padding: clamp(22px, 4vw, 52px);
  border-radius: var(--radius);
  background: var(--paper);
  color: var(--ink);
}
.prose--paper h2, .prose--paper h3, .prose--paper strong { color: #0A1526; }
.prose--paper a { color: #0F7A6C; border-bottom-color: rgba(15, 122, 108, .4); }
.prose--paper blockquote { border-left-color: #0F7A6C; color: #3A4C66; }
.prose--paper th, .prose--paper td { border-bottom-color: #C9D5E4; }
.prose--paper th { color: #4C6079; }

/* ---------- 9. 图片容器（供页面阶段放置图片） ---------- */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(140deg, #0A1526 0%, #14243E 55%, #0C1830 100%);
}
.media img { width: 100%; height: 100%; object-fit: cover; filter: saturate(.86) contrast(1.06); }
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(200deg, rgba(47, 227, 206, .14), transparent 58%);
}
.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--clip { clip-path: polygon(0 0, 100% 0, 100% 86%, 0 100%); }
.media-cap { margin-top: 8px; font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .06em; color: var(--mist); }

/* ---------- 10. 页头 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 300;
  padding: 10px 16px;
  border-radius: var(--radius);
  background: var(--cyan);
  color: #04121A;
  font-size: 14px;
  font-weight: 700;
  transform: translateY(-180%);
  transition: transform var(--t-fast) var(--ease);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  --header-h: 76px;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background var(--t-mid) var(--ease), border-color var(--t-mid) var(--ease);
}
.site-header[data-state="solid"] {
  --header-h: 64px;
  background: rgba(7, 14, 28, .95);
  border-bottom-color: var(--line);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  backdrop-filter: saturate(140%) blur(10px);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2.2vw, 30px);
  min-height: var(--header-h);
  flex-wrap: nowrap;
}
.header-rail {
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 0;
  background: linear-gradient(90deg, var(--cyan), var(--flare));
  transition: width 120ms linear;
}

/* 品牌 */
.brand { display: inline-flex; align-items: center; gap: 12px; flex: 0 0 auto; }
.brand-mark {
  position: relative;
  width: 26px;
  height: 26px;
  flex: 0 0 auto;
  border: 1px solid var(--cyan);
  transform: skewX(-12deg);
}
.brand-mark::before {
  content: "";
  position: absolute;
  inset: 5px;
  background: var(--cyan);
  opacity: .85;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.12; }
.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--silver);
  white-space: nowrap;
}
.brand-latin {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: var(--cyan);
}
.brand-tag {
  flex: 0 0 auto;
  margin-left: 4px;
  padding-left: 14px;
  border-left: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--mist);
  white-space: nowrap;
}

/* 导航 */
.main-nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  margin-left: auto;
}
.nav-list { display: flex; align-items: center; gap: clamp(8px, 1.5vw, 24px); }
.nav-list a {
  position: relative;
  display: block;
  padding: 8px 2px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .03em;
  color: var(--silver);
  opacity: .86;
  transition: color var(--t-fast) var(--ease), opacity var(--t-fast) var(--ease);
}
.nav-list a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-fast) var(--ease);
}
.nav-list a:hover { opacity: 1; }
.nav-list a:hover::after { transform: scaleX(1); }
.nav-list a[aria-current="page"] { color: var(--cyan); opacity: 1; }
.nav-list a[aria-current="page"]::after { transform: scaleX(1); }

.nav-quick {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-left: clamp(12px, 2vw, 24px);
  border-left: 1px solid var(--line);
}
.nav-quick-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--mist);
}
.quick-link {
  flex: 0 0 auto;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 700;
  color: var(--silver);
  white-space: nowrap;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease),
              border-color var(--t-fast) var(--ease);
}
.quick-link:hover { color: var(--cyan); border-color: var(--cyan); background: rgba(47, 227, 206, .07); }
.quick-link--accent {
  color: #FFD9CF;
  border-color: rgba(255, 90, 54, .55);
  background: rgba(255, 90, 54, .12);
}
.quick-link--accent:hover { color: #1A0600; background: var(--flare); border-color: var(--flare); }

/* 菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--silver);
  background: rgba(12, 24, 48, .6);
}
.nav-toggle-bars { position: relative; display: block; width: 18px; height: 12px; }
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--cyan);
  transition: transform var(--t-fast) var(--ease), top var(--t-fast) var(--ease), bottom var(--t-fast) var(--ease);
}
.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { bottom: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before { top: 5px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { bottom: 5px; transform: rotate(-45deg); }
.nav-toggle-text { display: inline; }

/* ---------- 11. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(7, 14, 28, .35) 0%, #070E1C 42%, #050A14 100%);
  color: var(--mist);
  font-size: 14.5px;
}
.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(340px, 42%);
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), transparent);
}
.footer-grid {
  display: grid;
  grid-template-columns: minmax(250px, 1fr) minmax(0, 1.5fr);
  gap: clamp(28px, 5vw, 66px);
  padding-block: clamp(42px, 6vw, 76px) clamp(26px, 4vw, 44px);
}
.footer-brand { display: flex; flex-direction: column; align-items: flex-start; gap: 14px; }
.brand--footer .brand-name { font-size: 20px; letter-spacing: .08em; }
.footer-line { font-size: 14px; color: var(--mist); max-width: 32ch; }
.footer-meters {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px 18px;
  width: 100%;
  margin-top: 4px;
}
.meter-item { padding-left: 12px; border-left: 1px solid var(--line); }
.meter-key { font-size: 12px; letter-spacing: .04em; color: var(--mist); }
.meter-val {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.35;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}
.footer-cols {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: clamp(20px, 3vw, 40px);
}
.footer-col-title {
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .14em;
  color: var(--silver);
}
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-link {
  font-size: 14.5px;
  color: var(--mist);
  transition: color var(--t-fast) var(--ease), padding-left var(--t-fast) var(--ease);
}
.footer-link:hover { color: var(--cyan); padding-left: 6px; }
.footer-link[aria-current="page"] { color: var(--cyan); }
.footer-meta {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-block: 22px 36px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--mist);
}
.footer-contact {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.9;
  letter-spacing: .02em;
  color: var(--silver);
  max-width: 100%;
}
.footer-note { max-width: 82ch; line-height: 1.75; }
.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--mist);
}

/* 返回顶部 */
.to-top {
  position: fixed;
  right: clamp(14px, 3vw, 32px);
  bottom: clamp(14px, 3vw, 32px);
  z-index: 120;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--cyan);
  border-radius: var(--radius);
  background: rgba(7, 14, 28, .92);
  color: var(--cyan);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--t-fast) var(--ease), transform var(--t-fast) var(--ease),
              background var(--t-fast) var(--ease), color var(--t-fast) var(--ease),
              visibility 0s linear var(--t-fast);
}
.to-top::before { content: "↑"; font-family: var(--font-mono); font-size: 14px; }
.to-top[data-visible="true"] {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition-delay: 0s, 0s, 0s, 0s, 0s;
}
.to-top:hover { background: var(--cyan); color: #04121A; }

/* ---------- 12. 显现动效 ---------- */
html[data-reveal-ready] [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--t-slow) var(--ease), transform var(--t-slow) var(--ease);
}
html[data-reveal-ready] [data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- 13. 响应式 ---------- */
@media (max-width: 1280px) {
  .brand-tag { display: none; }
}
@media (max-width: 1200px) {
  .nav-quick-label { display: none; }
}
@media (max-width: 1100px) {
  .nav-toggle { display: inline-flex; }
  .main-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(420px, 92vw);
    margin-left: 0;
    padding: 92px var(--gutter) 40px;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(6, 12, 24, .985);
    border-left: 1px solid var(--line);
    overflow-y: auto;
    overscroll-behavior: contain;
    transform: translateX(102%);
    visibility: hidden;
    transition: transform var(--t-mid) var(--ease), visibility 0s linear var(--t-mid);
    box-shadow: -24px 0 60px rgba(0, 0, 0, .5);
  }
  .main-nav[data-open] {
    transform: none;
    visibility: visible;
    transition: transform var(--t-mid) var(--ease), visibility 0s linear 0s;
  }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-list a {
    padding: 16px 2px;
    border-bottom: 1px solid var(--line);
    font-family: var(--font-display);
    font-size: 19px;
    font-weight: 700;
    opacity: 1;
  }
  .nav-list a::after { display: none; }
  .nav-quick {
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 26px;
    padding-left: 0;
    border-left: 0;
  }
  .nav-quick-label { display: block; width: 100%; margin-bottom: 2px; }
}
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .grid--12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  body { font-size: 16.5px; }
  .site-header { --header-h: 66px; }
  .header-inner { gap: 12px; }
  .sec-head { gap: 12px; }
  .footer-meters { gap: 10px 14px; }
  .to-top { padding: 9px 13px; font-size: 12px; }
}
@media (max-width: 560px) {
  .brand-name { font-size: 16px; }
  .brand-latin { font-size: 9px; letter-spacing: .18em; }
  .brand-mark { width: 22px; height: 22px; }
  .nav-toggle-text { display: none; }
  .grid--12 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-meters { grid-template-columns: minmax(0, 1fr); }
  .footer-contact { font-size: 12px; }
  .btn { width: 100%; }
}

/* ---------- 14. 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;
  }
  html[data-reveal-ready] [data-reveal] { opacity: 1; transform: none; }
  .card:hover, .btn--primary:hover, .btn--flare:hover, .btn--ghost:hover { transform: none; }
  .footer-link:hover { padding-left: 0; }
  .meter-fill { transition: none; }
}