/* ============================================================
   天行体育汇 · 共享样式 /assets/site.css
   玻璃层叠：彩色底 → 半透明玻璃面板 → 悬浮数据卡
   ============================================================ */

/* --- 设计定稿变量（原样保留） --- */
:root {
  --color-surface: #fefefe;
  --color-surface-alt: #f5f5f5;
  --color-surface-deep: #e8e9e9;
  --color-ink: #434b51;
  --color-ink-soft: #677279;
  --color-ink-muted: #768189;
  --color-line: #dcdedf;
  --color-primary: #3c7ca9;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e3ecf2;
  --color-accent: #1d46e2;
  --color-accent-ink: #ffffff;
  --color-highlight: #d6ddf9;
  --color-focus: #113fee;
  --color-contrast-surface: #12171b;
  --color-contrast-ink: #e4e6e7;
  --color-contrast-line: #404548;
  --color-contrast-accent: #5d7aea;
  --overlay-scrim: linear-gradient(180deg, rgba(18, 23, 27, 0.35) 0%, rgba(18, 23, 27, 0.72) 55%, rgba(18, 23, 27, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 10.4px;
  --text-sm: 13.9px;
  --text-base: 16px;
  --text-lg: 21.3px;
  --text-xl: 28.4px;
  --text-2xl: 37.9px;
  --text-3xl: 50.5px;
  --text-4xl: 67.3px;
  --text-display: clamp(51px, 10.5vw, 134px);
  --text-figure: clamp(42px, 7.5vw, 96px);
  --weight-heading: 628;
  --weight-body: 400;
  --leading-body: 1.77;
  --leading-heading: 1.23;
  --tracking-heading: 0.006em;
  --radius-sm: 14px;
  --radius-md: 18px;
  --radius-lg: 21px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(67, 75, 81, 0.08);
  --shadow-2: 0 18px 44px rgba(67, 75, 81, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1200px;
  --measure: 74ch;
  --gutter: 32px;
  --section-y: 100px;
  --section-y-lg: 140px;
}

/* --- 派生令牌（全部由定稿变量计算，不引入新颜色） --- */
:root {
  --rail-w: 252px;
  --glass-panel: color-mix(in srgb, var(--color-surface) 84%, transparent);
  --glass-soft: color-mix(in srgb, var(--color-surface) 10%, transparent);
  --edge-bright: color-mix(in srgb, var(--color-surface) 58%, transparent);
  --edge-dim: color-mix(in srgb, var(--color-surface) 24%, transparent);
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
  --dur: 220ms;
  --dur-fast: 140ms;
}

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

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

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface-deep);
  background-image:
    radial-gradient(920px 520px at 90% -8%, color-mix(in srgb, var(--color-primary) 30%, transparent), transparent 70%),
    radial-gradient(720px 480px at 2% 16%, color-mix(in srgb, var(--color-accent) 14%, transparent), transparent 72%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; }

button { font: inherit; }

::selection {
  background: var(--color-highlight);
  color: var(--color-accent);
}

/* --- 中文排版与基础文字 --- */
h1, h2, h3, h4 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

h1 { font-size: var(--text-2xl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }
h4 { font-size: var(--text-base); letter-spacing: 0.1em; }

p { margin: 0 0 var(--space-3); }

p:last-child { margin-bottom: 0; }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease), text-decoration-color var(--dur-fast) var(--ease);
}

a:hover { text-decoration: underline; text-underline-offset: 4px; }

strong { font-weight: var(--weight-heading); }

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

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

.rail :focus-visible {
  outline-color: var(--color-highlight);
}

/* --- 布局容器 --- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow { max-width: 880px; }

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-6); }

.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.stack--tight { gap: var(--space-2); }
.stack--loose { gap: var(--space-6); }

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}

.col-3 { grid-column: span 3; }
.col-4 { grid-column: span 4; }
.col-5 { grid-column: span 5; }
.col-6 { grid-column: span 6; }
.col-7 { grid-column: span 7; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }

/* --- 面板：半透明玻璃叠在彩色底上，只用一条亮线勾边 --- */
.panel {
  position: relative;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border-top: var(--border-thin) solid var(--edge-bright);
  border-left: var(--border-thin) solid var(--edge-dim);
  background: var(--glass-panel);
  box-shadow: var(--shadow-1);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  backdrop-filter: blur(16px) saturate(150%);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.panel--flat {
  background: var(--color-surface-alt);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.panel--primary {
  background: linear-gradient(160deg,
    color-mix(in srgb, var(--color-primary) 92%, var(--color-accent)) 0%,
    var(--color-primary) 62%,
    color-mix(in srgb, var(--color-primary) 74%, var(--color-contrast-surface)) 100%);
  color: var(--color-primary-ink);
  border-top-color: color-mix(in srgb, var(--color-surface) 46%, transparent);
  border-left-color: color-mix(in srgb, var(--color-surface) 20%, transparent);
}

.panel--primary h1,
.panel--primary h2,
.panel--primary h3,
.panel--primary a,
.panel--primary .lead { color: var(--color-primary-ink); }

.panel--dark {
  background: linear-gradient(170deg,
    color-mix(in srgb, var(--color-accent) 28%, var(--color-contrast-surface)) 0%,
    var(--color-contrast-surface) 58%);
  color: var(--color-contrast-ink);
  border-top-color: color-mix(in srgb, var(--color-contrast-ink) 30%, transparent);
  border-left-color: var(--color-contrast-line);
  box-shadow: var(--shadow-2);
}

.panel--dark h1,
.panel--dark h2,
.panel--dark h3,
.panel--dark .lead { color: var(--color-contrast-ink); }

.panel--dark a { color: var(--color-contrast-accent); }

.panel--interactive:hover,
.panel--interactive:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
  border-top-color: var(--color-accent);
}

.panel__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.panel__title { margin: 0; }

/* --- 标签与强调 --- */
.kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.kicker::before {
  content: "";
  width: 28px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--color-accent), transparent);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 4px var(--space-2);
  border-radius: var(--radius-pill);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.tag--accent {
  background: var(--color-highlight);
  color: var(--color-accent);
}

.tag--dark {
  background: color-mix(in srgb, var(--color-surface) 14%, transparent);
  color: var(--color-contrast-ink);
}

.lead {
  max-width: var(--measure);
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
}

.figure {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

.panel--dark .figure { color: var(--color-contrast-ink); }

.figure--glow {
  color: var(--color-contrast-accent);
  text-shadow: 0 0 34px color-mix(in srgb, var(--color-contrast-accent) 60%, transparent);
}

.figure__unit {
  display: block;
  margin-top: var(--space-1);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.panel--dark .figure__unit { color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent); }

/* --- 按钮 --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  min-height: 44px;
  padding: 0 var(--space-3);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-pill);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  letter-spacing: 0.06em;
  text-decoration: none;
  cursor: pointer;
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    background-color var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.btn:hover { text-decoration: none; }

.btn--primary {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  box-shadow: var(--shadow-1);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.btn--ghost {
  background: color-mix(in srgb, var(--color-surface) 74%, transparent);
  border-color: var(--color-line);
  color: var(--color-ink);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
}

.btn--ghost:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.btn--rail {
  width: 100%;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  box-shadow: 0 10px 26px color-mix(in srgb, var(--color-contrast-surface) 45%, transparent);
}

.btn--rail:hover {
  transform: translateY(-2px);
  background: color-mix(in srgb, var(--color-accent) 84%, var(--color-surface));
}

/* --- 面包屑 --- */
.breadcrumb { margin-bottom: var(--space-4); }

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.breadcrumb li + li::before {
  content: "/";
  color: var(--color-line);
}

.breadcrumb a { color: var(--color-ink-soft); }
.breadcrumb a:hover { color: var(--color-accent); }

.breadcrumb [aria-current="page"] {
  color: var(--color-ink);
  font-weight: var(--weight-heading);
}

/* --- 图片容器 --- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-lg);
  background:
    radial-gradient(120% 90% at 20% 0%, color-mix(in srgb, var(--color-primary) 62%, transparent), transparent 62%),
    linear-gradient(160deg, var(--color-primary), var(--color-contrast-surface));
  box-shadow: var(--shadow-1);
}

.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.media-frame__body {
  position: absolute;
  inset-inline: 0;
  bottom: 0;
  padding: var(--space-3);
  color: var(--color-contrast-ink);
}

.media-frame__body h3,
.media-frame__body p { color: var(--color-contrast-ink); }

/* --- 可展开说明面板 --- */
.expand {
  padding: 0 var(--space-3);
  border-radius: var(--radius-md);
  border-top: var(--border-thin) solid var(--edge-bright);
  border-left: var(--border-thin) solid var(--edge-dim);
  background: color-mix(in srgb, var(--color-surface) 72%, transparent);
}

.expand + .expand { margin-top: var(--space-2); }

.expand > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-3) 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  letter-spacing: 0.08em;
  color: var(--color-ink);
}

.expand > summary::-webkit-details-marker { display: none; }

.expand > summary::after {
  content: "";
  flex: none;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--color-accent);
  border-bottom: 2px solid var(--color-accent);
  transform: rotate(45deg) translateY(-2px);
  transition: transform var(--dur) var(--ease);
}

.expand[open] > summary::after { transform: rotate(-135deg) translateY(-2px); }

.expand__body {
  padding-bottom: var(--space-3);
  color: var(--color-ink-soft);
}

/* --- 显现 --- */
html[data-js="on"] [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 420ms var(--ease), transform 420ms var(--ease);
}

html[data-js="on"] [data-reveal="in"] {
  opacity: 1;
  transform: none;
}

/* ============================================================
   头部：彩色玻璃侧轨 + 移动抽屉
   ============================================================ */
.site-header { position: relative; z-index: 70; }

.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 200;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  text-decoration: none;
  transform: translateY(-200%);
  transition: transform var(--dur) var(--ease);
}

.skip-link:focus { transform: translateY(0); }

.rail {
  position: fixed;
  inset-block: 0;
  inset-inline-start: 0;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-6) var(--space-4);
  overflow-y: auto;
  overscroll-behavior: contain;
  background-image: linear-gradient(172deg,
    color-mix(in srgb, var(--color-primary) 86%, var(--color-accent)) 0%,
    color-mix(in srgb, var(--color-primary) 66%, var(--color-contrast-surface)) 46%,
    var(--color-contrast-surface) 100%);
}

.rail::before {
  content: "";
  position: absolute;
  inset: var(--space-2);
  border-radius: var(--radius-lg);
  border-top: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 62%, transparent);
  border-left: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 28%, transparent);
  background: var(--glass-soft);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  backdrop-filter: blur(18px) saturate(140%);
  pointer-events: none;
}

.rail::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  bottom: 0;
  height: 38%;
  clip-path: polygon(0 46%, 100% 0, 100% 100%, 0 100%);
  background: linear-gradient(200deg, color-mix(in srgb, var(--color-accent) 58%, transparent), transparent 76%);
  opacity: 0.55;
  pointer-events: none;
}

.rail > * {
  position: relative;
  z-index: 1;
}

.rail__head {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-surface);
  text-decoration: none;
}

.brand:hover { text-decoration: none; }

.brand__mark {
  flex: none;
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  border-top: var(--border-thin) solid var(--edge-bright);
  border-left: var(--border-thin) solid var(--edge-dim);
  background: color-mix(in srgb, var(--color-surface) 16%, transparent);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-surface);
}

.brand__text { display: block; }

.brand__line {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.3;
  letter-spacing: 0.1em;
  color: var(--color-surface);
}

.brand__tagline {
  display: block;
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: color-mix(in srgb, var(--color-contrast-ink) 74%, transparent);
}

.update-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  align-self: flex-start;
  margin: 0;
  padding: 4px var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 24%, transparent);
  background: color-mix(in srgb, var(--color-surface) 10%, transparent);
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  color: var(--color-contrast-ink);
}

.update-badge__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-contrast-accent);
  box-shadow: 0 0 12px var(--color-contrast-accent);
  animation: txs-pulse 3.2s var(--ease) infinite;
}

@keyframes txs-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.45; transform: scale(0.78); }
}

.rail__meter {
  height: 3px;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-surface) 14%, transparent);
  overflow: hidden;
}

.rail__meter span {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--color-contrast-accent), color-mix(in srgb, var(--color-surface) 82%, transparent));
}

.rail__nav {
  display: flex;
  flex: 1 1 auto;
  flex-direction: column;
  gap: var(--space-4);
  min-height: 0;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 11px var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  letter-spacing: 0.1em;
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
  text-decoration: none;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.nav-link:hover {
  background: color-mix(in srgb, var(--color-surface) 12%, transparent);
  color: var(--color-surface);
  text-decoration: none;
  transform: translateX(2px);
}

.nav-link__tick {
  flex: none;
  width: 3px;
  height: 16px;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-surface) 26%, transparent);
  transition: height var(--dur) var(--ease), background-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.nav-link[aria-current="page"] {
  background: color-mix(in srgb, var(--color-surface) 15%, transparent);
  color: var(--color-surface);
}

.nav-link[aria-current="page"] .nav-link__tick {
  height: 26px;
  background: var(--color-contrast-accent);
  box-shadow: 0 0 14px color-mix(in srgb, var(--color-contrast-accent) 78%, transparent);
}

.rail__foot {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: auto;
}

.rail__note {
  display: none;
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.5;
  letter-spacing: 0.1em;
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  min-height: 44px;
  padding: var(--space-1) var(--space-2);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 28%, transparent);
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-surface) 12%, transparent);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  cursor: pointer;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.nav-toggle:hover {
  transform: translateY(-2px);
  border-color: var(--color-highlight);
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bars i {
  display: block;
  height: 2px;
  border-radius: var(--radius-pill);
  background: currentColor;
  transition: transform var(--dur) var(--ease);
}

.site-header[data-nav-open] .nav-toggle__bars i:first-child { transform: translateY(3px) rotate(45deg); }
.site-header[data-nav-open] .nav-toggle__bars i:last-child { transform: translateY(-3px) rotate(-45deg); }

.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 75;
  background: color-mix(in srgb, var(--color-contrast-surface) 62%, transparent);
  -webkit-backdrop-filter: blur(3px);
  backdrop-filter: blur(3px);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--dur) var(--ease), visibility var(--dur) var(--ease);
}

.site-header[data-nav-open] .nav-scrim {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

/* ============================================================
   页脚：浅色底上的三块玻璃卡
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: var(--section-y-lg);
  padding-block: var(--section-y) var(--space-6);
  background-image:
    radial-gradient(680px 420px at 10% 0%, color-mix(in srgb, var(--color-primary) 34%, transparent), transparent 70%),
    radial-gradient(560px 380px at 92% 18%, color-mix(in srgb, var(--color-accent) 22%, transparent), transparent 72%),
    linear-gradient(180deg, var(--color-surface-deep), color-mix(in srgb, var(--color-surface) 72%, var(--color-surface-deep)));
  background-repeat: no-repeat;
}

.foot-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.foot-head__brand { min-width: 0; }

.foot-brand {
  margin: 0 0 var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: 0.14em;
  color: var(--color-ink);
}

.foot-line {
  margin: 0;
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  color: var(--color-ink-soft);
}

.foot-grid {
  display: grid;
  grid-template-columns: 1.5fr 1.15fr 0.85fr;
  gap: var(--gutter);
  align-items: start;
}

.foot-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.foot-panel__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.3em;
  color: var(--color-primary);
}

.foot-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin: 0;
  padding: 0;
  list-style: none;
}

.foot-item {
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-ink-soft);
}

.foot-item--line {
  position: relative;
  padding-left: var(--space-2);
}

.foot-item--line::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 6px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
}

.foot-item--note {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.foot-item__label {
  display: block;
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.foot-item__value {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-base);
  letter-spacing: 0.02em;
  color: var(--color-ink);
  word-break: break-all;
}

.foot-item__value--text {
  font-family: var(--font-body);
  word-break: normal;
}

.copy-btn {
  margin-inline-start: var(--space-1);
  min-height: 28px;
  padding: 2px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-surface) 82%, transparent);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.copy-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.copy-btn[data-copied="true"] {
  border-color: var(--color-accent);
  background: var(--color-highlight);
  color: var(--color-accent);
}

.foot-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: var(--space-8);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.foot-legal p { margin: 0; }

/* ============================================================
   断点
   ============================================================ */
@media (min-width: 1024px) {
  body { padding-inline-start: var(--rail-w); }

  .skip-link { left: calc(var(--rail-w) + var(--space-2)); }
}

@media (max-width: 1023px) {
  body { padding-inline-start: 0; }

  .section { padding-block: 72px; }
  .section--lg { padding-block: 88px; }

  .site-header {
    position: sticky;
    top: 0;
    z-index: 70;
  }

  .rail {
    position: static;
    width: 100%;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    overflow: visible;
    background-image: linear-gradient(120deg,
      color-mix(in srgb, var(--color-primary) 86%, var(--color-accent)) 0%,
      color-mix(in srgb, var(--color-primary) 62%, var(--color-contrast-surface)) 62%,
      var(--color-contrast-surface) 100%);
  }

  .rail::before {
    inset: var(--space-1) var(--space-2);
    border-radius: var(--radius-md);
  }

  .rail::after { display: none; }

  .rail__head {
    position: relative;
    z-index: 95;
    flex-direction: row;
    align-items: center;
    gap: var(--space-2);
  }

  .update-badge,
  .rail__meter { display: none; }

  .brand__mark {
    width: 36px;
    height: 36px;
    font-size: var(--text-base);
  }

  .brand__line { font-size: var(--text-base); }
  .brand__tagline { font-size: var(--text-xs); letter-spacing: 0.12em; }

  .nav-toggle {
    display: inline-flex;
    position: relative;
    z-index: 95;
  }

  .rail__nav {
    position: fixed;
    inset-block: 0;
    inset-inline-start: 0;
    z-index: 80;
    width: min(340px, 86vw);
    flex: none;
    flex-direction: column;
    gap: var(--space-3);
    padding: calc(var(--space-8) + var(--space-4)) var(--space-4) var(--space-6);
    overflow-y: auto;
    overscroll-behavior: contain;
    border-right: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 20%, transparent);
    border-start-end-radius: var(--radius-lg);
    border-end-end-radius: var(--radius-lg);
    background-image: linear-gradient(170deg,
      color-mix(in srgb, var(--color-primary) 58%, var(--color-contrast-surface)) 0%,
      var(--color-contrast-surface) 100%);
    box-shadow: var(--shadow-2);
    transform: translateX(-102%);
    visibility: hidden;
    transition: transform var(--dur) var(--ease), visibility var(--dur) var(--ease);
  }

  .rail__nav::before {
    content: "";
    position: absolute;
    inset: var(--space-2);
    border-radius: var(--radius-lg);
    border-top: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 42%, transparent);
    border-left: var(--border-thin) solid color-mix(in srgb, var(--color-surface) 22%, transparent);
    background: var(--glass-soft);
    pointer-events: none;
  }

  .rail__nav > * {
    position: relative;
    z-index: 1;
  }

  .rail__nav[data-open] {
    transform: translateX(0);
    visibility: visible;
  }

  .nav-link {
    padding: var(--space-3) var(--space-3);
    font-size: var(--text-lg);
  }

  .rail__note { display: block; }

  .grid { gap: var(--space-3); }

  .col-3,
  .col-4,
  .col-5 { grid-column: span 6; }

  .col-7,
  .col-8 { grid-column: span 12; }

  .foot-grid { grid-template-columns: 1fr 1fr; }
  .foot-grid > :first-child { grid-column: 1 / -1; }

  .site-footer {
    margin-top: 88px;
    padding-block: 72px var(--space-6);
  }

  .foot-head { margin-bottom: var(--space-4); }
  .foot-legal { margin-top: var(--space-6); }
}

@media (max-width: 639px) {
  :root { --gutter: 24px; }

  .col-3,
  .col-4,
  .col-5,
  .col-6 { grid-column: span 12; }

  .panel { padding: var(--space-3); }

  .foot-grid { grid-template-columns: 1fr; }

  .foot-head { flex-direction: column; align-items: flex-start; }

  .brand__tagline { display: none; }

  .btn { width: 100%; }

  .foot-head .btn { width: auto; }
}

/* ============================================================
   动效降级
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
  }

  html[data-js="on"] [data-reveal],
  html[data-js="on"] [data-reveal="in"] {
    opacity: 1;
    transform: none;
  }

  .panel--interactive:hover,
  .btn:hover,
  .nav-toggle:hover,
  .nav-link:hover { transform: none; }
}