/* ============================================================
   云开赛场 · 共享样式  /assets/site.css
   头部 · 页脚 · 排版 · 通用组件 · 响应式
   ============================================================ */

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

html, body, h1, h2, h3, h4, h5, p, ul, ol, dl, dd, figure, blockquote, form { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { max-width: 100%; }
button { font: inherit; color: inherit; }
a { color: inherit; }

/* ---------- 2. Tokens ---------- */
:root {
  --ink: #061321;          /* 深空蓝 */
  --ink-teal: #072A2E;     /* 深蓝绿 */
  --ink-indigo: #1A1738;   /* 靛紫 */
  --ink-wine: #5C2038;     /* 酒红 */
  --cyan: #35F2D0;         /* 电光青 */
  --orange: #FF8A3D;       /* 信号橙 */
  --mist: #EAF6F4;         /* 浅雾白 */
  --cloud: #93AEB8;        /* 云灰 */
  --slate: #123742;        /* 青灰 */
  --line: #1E5A63;         /* 线框青 */
  --line-soft: rgba(30, 90, 99, 0.55);

  --rail-w: 88px;
  --bar-h: 64px;
  --gutter: clamp(20px, 4vw, 56px);
  --radius: 14px;

  --font-sans: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 3. Base ---------- */
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  padding-left: var(--rail-w);
  padding-top: var(--bar-h);
  background-color: var(--ink);
  background-image:
    radial-gradient(1200px 620px at 80% -12%, rgba(53, 242, 208, 0.10), transparent 62%),
    radial-gradient(880px 520px at 4% 108%, rgba(255, 138, 61, 0.07), transparent 60%),
    linear-gradient(rgba(30, 90, 99, 0.15) 1px, transparent 1px),
    linear-gradient(90deg, rgba(30, 90, 99, 0.15) 1px, transparent 1px);
  background-size: auto, auto, 64px 64px, 64px 64px;
  background-attachment: fixed, fixed, fixed, fixed;
  color: var(--mist);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--mist);
}

p { margin-bottom: 1em; }

a { text-decoration: none; }

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

::selection { background: rgba(53, 242, 208, 0.28); color: var(--mist); }

/* ---------- 4. 排版工具 ---------- */
.wrap {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

.section { padding-top: clamp(36px, 6vw, 88px); padding-bottom: clamp(36px, 6vw, 88px); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--orange);
}

.display-1 {
  font-size: clamp(40px, 6vw, 86px);
  line-height: 1.02;
  letter-spacing: -0.03em;
  margin-bottom: 0.35em;
}

.display-2 {
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.1;
  margin-bottom: 0.5em;
}

.lead {
  max-width: 60ch;
  font-size: clamp(17px, 1.6vw, 20px);
  line-height: 1.7;
  color: rgba(234, 246, 244, 0.82);
}

.prose {
  max-width: 68ch;
  font-size: 16.5px;
  line-height: 1.8;
  color: rgba(234, 246, 244, 0.86);
}
.prose p + p { margin-top: 1em; }
.prose h2, .prose h3 { margin-top: 1.6em; margin-bottom: 0.5em; }
.prose h2 { font-size: clamp(24px, 3vw, 32px); }
.prose h3 { font-size: 20px; }
.prose ul, .prose ol { margin: 1em 0; padding-left: 1.2em; list-style: disc; }
.prose li { margin-bottom: 0.4em; }
.prose strong { color: var(--cyan); font-weight: 700; }

.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  font-variant-numeric: tabular-nums;
}

/* ---------- 5. 网格 ---------- */
.grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}
.grid--split { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); align-items: start; }
.grid--split-rev { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); align-items: start; }
.grid--cards { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }

/* ---------- 6. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.3;
  cursor: pointer;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.btn--primary { background: var(--cyan); color: #04141c; }
.btn--primary:hover { background: var(--mist); color: #04141c; }
.btn--accent { background: var(--orange); color: #1b0d04; }
.btn--accent:hover { background: var(--mist); color: #1b0d04; }
.btn--ghost { background: transparent; border-color: var(--line); color: var(--mist); }
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); }
.btn--small { padding: 8px 14px; font-size: 12.5px; }

/* ---------- 7. 组件：面板 / 标签 / 统计 ---------- */
.panel {
  padding: clamp(18px, 2.4vw, 28px);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: linear-gradient(160deg, rgba(18, 55, 66, 0.72), rgba(7, 42, 46, 0.46));
}

.card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(16px, 2vw, 24px);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: linear-gradient(165deg, rgba(18, 55, 66, 0.6), rgba(6, 19, 33, 0.5));
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.card:hover { border-color: var(--cyan); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid rgba(53, 242, 208, 0.35);
  border-radius: 6px;
  background: rgba(53, 242, 208, 0.10);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  white-space: nowrap;
}
.tag--accent {
  color: var(--orange);
  border-color: rgba(255, 138, 61, 0.4);
  background: rgba(255, 138, 61, 0.12);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  border: 1px solid var(--line-soft);
  border-radius: 12px;
  background: rgba(18, 55, 66, 0.42);
}
.stat-value {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cloud);
}

.divider {
  height: 1px;
  margin: clamp(24px, 4vw, 40px) 0;
  border: 0;
  background: linear-gradient(90deg, var(--line), rgba(30, 90, 99, 0));
}

/* ---------- 8. 框景 ---------- */
.frame {
  position: relative;
  padding: clamp(20px, 3vw, 40px);
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 6px);
  background: linear-gradient(150deg, rgba(7, 42, 46, 0.55), rgba(6, 19, 33, 0.25));
}
.frame::before,
.frame::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: 2px solid var(--cyan);
}
.frame::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
  border-top-left-radius: 6px;
}
.frame::after {
  right: -1px;
  bottom: -1px;
  border-top: 0;
  border-left: 0;
  border-bottom-right-radius: 6px;
}

/* ---------- 9. 面包屑 ---------- */
.breadcrumbs {
  padding: 18px 0 4px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--cloud);
}
.breadcrumbs ol { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.breadcrumbs li { display: inline-flex; align-items: center; gap: 6px; }
.breadcrumbs li + li::before { content: "/"; color: var(--line); }
.breadcrumbs a { color: var(--cloud); transition: color 0.18s var(--ease); }
.breadcrumbs a:hover { color: var(--cyan); }
.breadcrumbs [aria-current="page"] { color: var(--mist); }

/* ---------- 10. 图片容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 120% at 18% 0%, rgba(53, 242, 208, 0.22), transparent 56%),
    radial-gradient(90% 90% at 92% 100%, rgba(255, 138, 61, 0.16), transparent 58%),
    linear-gradient(140deg, var(--ink-indigo), #061321 55%, #072A2E);
}
.media-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame__caption {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  padding: 12px 14px;
  background: linear-gradient(transparent, rgba(4, 12, 20, 0.88));
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

/* ---------- 11. 分段标签页 ---------- */
.tabs { margin-bottom: clamp(20px, 3vw, 32px); }
.tablist {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line-soft);
  border-radius: 999px;
  background: rgba(6, 19, 33, 0.6);
}
.tab {
  appearance: none;
  padding: 8px 16px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--cloud);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease);
}
.tab:hover { color: var(--mist); }
.tab[aria-selected="true"] { background: var(--cyan); color: #04141c; }
.tabpanel { padding-top: 6px; }
.tabpanel[hidden] { display: none; }

/* ---------- 12. 显现与动效 ---------- */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}
html.js [data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}

/* ============================================================
   13. 头部
   ============================================================ */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 10px 18px;
  border-radius: 8px;
  background: var(--cyan);
  color: #04141c;
  font-weight: 700;
  transform: translateY(-220%);
  transition: transform 0.18s var(--ease);
  pointer-events: auto;
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  grid-template-rows: var(--bar-h) minmax(0, 1fr);
  pointer-events: none;
}

/* 左侧品牌轨道 */
.rail {
  grid-column: 1;
  grid-row: 1 / span 2;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 14px 10px 18px;
  overflow-y: auto;
  background: linear-gradient(180deg, #04101c 0%, #06202a 52%, #051520 100%);
  border-right: 1px solid var(--line-soft);
  pointer-events: auto;
  scrollbar-width: none;
}
.rail::-webkit-scrollbar { display: none; }
.rail::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 3px;
  height: 100%;
  background: repeating-linear-gradient(180deg, var(--line) 0 1px, transparent 1px 14px);
  opacity: 0.5;
  pointer-events: none;
}

.brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 6px 2px 14px;
  border-bottom: 1px dashed var(--line-soft);
  text-align: center;
  color: var(--mist);
}
.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--cyan);
  border-radius: 9px;
  background: rgba(53, 242, 208, 0.10);
  font-size: 15px;
  font-weight: 800;
  color: var(--cyan);
  line-height: 1;
}
.brand-name {
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.02em;
  line-height: 1.2;
  white-space: nowrap;
}
.brand-sub {
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.5;
  letter-spacing: 0.14em;
  color: var(--cloud);
}
.brand:hover .brand-mark { background: var(--cyan); color: #04141c; }

.rail-nav {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  padding: 8px 0;
}
.nav-list { width: 100%; display: flex; flex-direction: column; gap: 2px; }
.nav-item { width: 100%; }
.nav-link {
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding: 9px 7px;
  border: 1px solid transparent;
  border-radius: 8px;
  color: var(--cloud);
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.nav-index {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.12em;
  color: var(--line);
  transition: color 0.18s var(--ease);
}
.nav-label {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.01em;
  white-space: nowrap;
}
.nav-link:hover {
  color: var(--mist);
  background: rgba(53, 242, 208, 0.07);
  border-color: var(--line-soft);
}
.nav-link[aria-current="page"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #04141c;
}
.nav-link[aria-current="page"] .nav-index { color: rgba(4, 20, 28, 0.7); }

.rail-cta {
  display: block;
  padding: 10px 6px;
  border: 1px solid var(--orange);
  border-radius: 10px;
  background: rgba(255, 138, 61, 0.10);
  color: var(--orange);
  font-size: 11px;
  font-weight: 700;
  line-height: 1.35;
  text-align: center;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease);
}
.rail-cta:hover { background: var(--orange); color: #1b0d04; }

/* 顶部条带 */
.topbar {
  grid-column: 2;
  grid-row: 1;
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 26px);
  padding: 0 var(--gutter) 0 clamp(14px, 2vw, 24px);
  background: linear-gradient(180deg, rgba(7, 42, 46, 0.96), rgba(6, 25, 35, 0.92));
  border-bottom: 1px solid var(--line-soft);
  pointer-events: auto;
  transition: box-shadow 0.2s var(--ease);
}
.site-header[data-scrolled="true"] .topbar { box-shadow: 0 10px 30px rgba(0, 0, 0, 0.45); }

.scroll-meter {
  position: absolute;
  right: 0;
  bottom: -1px;
  left: 0;
  height: 2px;
  background: rgba(30, 90, 99, 0.4);
  pointer-events: none;
}
.scroll-meter-fill {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--orange));
  transition: width 0.12s linear;
}

.topbar-brand {
  display: none;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--mist);
  white-space: nowrap;
}

.legend {
  display: flex;
  flex: 1 1 auto;
  align-items: center;
  gap: 6px;
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.legend::-webkit-scrollbar { display: none; }
.legend-item {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 5px 11px;
  border: 1px solid var(--line-soft);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.02em;
  color: var(--cloud);
  white-space: nowrap;
}
.legend-item:first-child {
  color: var(--cyan);
  border-color: rgba(53, 242, 208, 0.5);
  background: rgba(53, 242, 208, 0.08);
}
.legend-count { font-size: 10.5px; color: var(--orange); }

.topbar-cta {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--cyan);
  color: #04141c;
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
  transition: background-color 0.18s var(--ease);
}
.topbar-cta:hover { background: var(--mist); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: rgba(6, 19, 33, 0.6);
  color: var(--mist);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  cursor: pointer;
}
.nav-toggle-bars { display: inline-flex; flex-direction: column; gap: 3px; width: 16px; }
.nav-toggle-bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
  transition: transform 0.18s var(--ease), opacity 0.18s var(--ease);
}
.site-header[data-open="true"] .nav-toggle-bars span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-header[data-open="true"] .nav-toggle-bars span:nth-child(2) { opacity: 0; }
.site-header[data-open="true"] .nav-toggle-bars span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

.rail-scrim { display: none; }

/* ============================================================
   14. 页脚
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: clamp(40px, 7vw, 96px);
  padding: clamp(40px, 6vw, 72px) var(--gutter) 0;
  border-top: 1px solid var(--line-soft);
  background: linear-gradient(180deg, #05161f, #04101a 62%, #030c14);
  color: var(--cloud);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: -2px;
  right: 0;
  left: 0;
  height: 3px;
  background: repeating-linear-gradient(90deg,
    var(--cyan) 0 24px, transparent 24px 38px,
    var(--orange) 38px 42px, transparent 42px 66px);
  opacity: 0.75;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(24px, 4vw, 52px);
  padding-bottom: clamp(28px, 4vw, 44px);
}

.footer-brand { display: flex; flex-direction: column; gap: 14px; align-items: flex-start; }
.brand--footer {
  flex-direction: row;
  align-items: center;
  gap: 12px;
  padding: 0;
  border-bottom: 0;
  text-align: left;
}
.brand--footer .brand-sub { display: none; }
.brand--footer .brand-name { font-size: 16px; }

.footer-summary {
  max-width: 34ch;
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(147, 174, 184, 0.95);
}

.footer-coords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.footer-coords li {
  padding: 4px 9px;
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--cloud);
}

.footer-title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--cyan);
}
.footer-title::before {
  content: "▚";
  margin-right: 8px;
  color: var(--orange);
  font-size: 10px;
}

.footer-list { display: flex; flex-direction: column; gap: 8px; }
.footer-link {
  display: inline-block;
  font-size: 14px;
  color: var(--cloud);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.footer-link:hover { color: var(--mist); border-bottom-color: var(--cyan); }

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  padding: 20px 0;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.contact-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
}
.contact-key {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--line);
  text-transform: uppercase;
}
.contact-val { color: var(--mist); word-break: break-all; }

.copy-btn,
.to-top {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: transparent;
  color: var(--cloud);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.copy-btn:hover,
.to-top:hover { color: var(--cyan); border-color: var(--cyan); }
.copy-btn[data-copied="true"] {
  color: #04141c;
  background: var(--cyan);
  border-color: var(--cyan);
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 28px;
  padding: 18px 0 28px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--cloud);
}
.footer-copy, .footer-icp { margin: 0; }
.footer-icp { color: var(--line); }
.footer-icp:hover { color: var(--cloud); }

/* ============================================================
   15. 响应式
   ============================================================ */
@media (max-width: 1080px) {
  .legend-item:nth-child(n + 4) { display: none; }
}

@media (max-width: 900px) {
  :root { --bar-h: 56px; }

  body { padding-left: 0; padding-top: var(--bar-h); }
  body.nav-open { overflow: hidden; }

  .site-header {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: var(--bar-h) minmax(0, 1fr);
  }

  .topbar {
    grid-column: 1;
    grid-row: 1;
    gap: 10px;
    padding: 0 14px;
  }
  .topbar-brand { display: inline-flex; margin-right: auto; }
  .topbar-cta { display: none; }
  .nav-toggle { display: inline-flex; }
  .legend { display: none; }

  .rail {
    position: fixed;
    top: var(--bar-h);
    left: 0;
    z-index: 2;
    grid-column: 1;
    grid-row: 1;
    width: min(82vw, 320px);
    height: calc(100dvh - var(--bar-h));
    padding: 18px 16px 22px;
    border-right: 1px solid var(--cyan);
    box-shadow: 24px 0 60px rgba(0, 0, 0, 0.55);
    transform: translateX(-104%);
    transition: transform 0.24s var(--ease);
  }
  .site-header[data-open="true"] .rail { transform: translateX(0); }
  .rail::after { display: none; }

  .brand {
    flex-direction: row;
    align-items: center;
    gap: 10px;
    padding: 0 0 16px;
    text-align: left;
  }
  .brand-sub { display: none; }
  .brand-name { font-size: 16px; }

  .rail-nav { align-items: flex-start; padding: 12px 0; }
  .nav-list { gap: 4px; }
  .nav-link {
    flex-direction: row;
    align-items: center;
    gap: 12px;
    padding: 12px 12px;
    border-color: rgba(30, 90, 99, 0.35);
  }
  .nav-label { font-size: 15px; }
  .nav-index { font-size: 10.5px; color: var(--cloud); }
  .rail-cta { padding: 13px 12px; font-size: 13px; }

  .rail-scrim {
    position: fixed;
    inset: 0;
    z-index: 1;
    display: block;
    background: rgba(3, 10, 18, 0.66);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.24s var(--ease);
  }
  .site-header[data-open="true"] .rail-scrim { opacity: 1; pointer-events: auto; }

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

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

@media (max-width: 620px) {
  .display-1 { font-size: clamp(34px, 10vw, 46px); }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 26px; }
  .footer-contact { gap: 10px 18px; }
  .contact-item { font-size: 12.5px; }
  .footer-meta { justify-content: flex-start; }
  .tablist { width: 100%; }
  .tab { flex: 1 1 auto; text-align: center; }
}

/* ============================================================
   16. 可访问性
   ============================================================ */
@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;
  }
  html.js [data-reveal] { opacity: 1; transform: none; }
  .scroll-meter-fill { transition: none; }
}