/* ============================================================
   云体育官网 · 共享样式 /assets/site.css
   外框 + 赛道导航 + 数据脚注带
   ============================================================ */

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

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

body {
  margin: 0;
  padding-top: calc(var(--head-h) + var(--frame));
  background-color: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 34px 34px;
  background-position: -1px -1px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img, svg, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration-thickness: 2px; text-underline-offset: 0.18em; }
a:hover { text-decoration-color: var(--clay); }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4, p, dl, dd, dt, figure, blockquote { margin: 0; }

:focus-visible {
  outline: 3px solid var(--clay);
  outline-offset: 2px;
  border-radius: 6px;
}
.band--dark :focus-visible,
.site-footer :focus-visible,
.site-header.is-scrolled :focus-visible { outline-color: var(--neon); }

::selection { background: var(--sun); color: #FFFBF2; }

/* ---------- 2. 设计变量 ---------- */
:root {
  --paper: #F7F1E3;
  --ink: #0E1F19;
  --ink-soft: #3D4F47;
  --grass: #2E9E63;
  --clay: #C0492A;
  --sun: #E8753A;
  --neon: #1FD6D0;
  --gold: #E4B23C;
  --stone: #8C8877;
  --stone-lift: #A9A594;
  --card: #FFFBF2;
  --night: #14352A;
  --line: rgba(140, 136, 119, 0.42);
  --grid-line: rgba(14, 31, 25, 0.05);
  --head-h: 78px;
  --frame: 2px;
  --r-sm: 14px;
  --r-card: 20px;
  --r-media: 28px;
  --r-pill: 999px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --shadow-card: 0 18px 40px -28px rgba(14, 31, 25, 0.55);
  --font-display: "Barlow Condensed", "Oswald", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", Menlo, Consolas, "PingFang SC", monospace;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
}

/* 整站外框，始终压在内容之上 */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  border: var(--frame) solid var(--ink);
  pointer-events: none;
  z-index: 200;
}

/* ---------- 3. 中文排版 ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.02;
  text-wrap: balance;
}
h1 { font-size: clamp(40px, 6.4vw, 84px); }
h2 { font-size: clamp(28px, 3.4vw, 44px); }
h3 { font-size: clamp(21px, 2vw, 26px); }
h4 { font-size: clamp(18px, 1.6vw, 21px); }

p { text-wrap: pretty; }

.prose {
  max-width: 68ch;
  color: var(--ink-soft);
}
.prose p + p { margin-top: 1.05em; }
.prose a { color: var(--grass); font-weight: 500; }
.prose strong { color: var(--ink); font-weight: 700; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--clay);
}
.eyebrow::before {
  content: "";
  display: block;
  width: 26px;
  height: 2px;
  background: currentColor;
}
.band--dark .eyebrow { color: var(--neon); }

.data-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  line-height: 1;
}

/* ---------- 4. 布局容器 ---------- */
.wrap { width: min(1240px, 100% - 48px); margin-inline: auto; }
.wrap--narrow { width: min(760px, 100% - 48px); margin-inline: auto; }

.section { padding-block: clamp(56px, 8vw, 120px); }
.section__head { display: grid; gap: 14px; margin-bottom: clamp(28px, 4vw, 48px); }
.section__title { max-width: 22ch; }
.section__desc { max-width: 58ch; color: var(--ink-soft); font-size: 16.5px; }

.band { padding-block: clamp(56px, 8vw, 112px); }
.band--dark {
  background: var(--night);
  color: var(--card);
}
.band--dark .section__desc,
.band--dark .chapter__lead,
.band--dark .stat__label { color: var(--stone-lift); }
.band--dark .chapter__num {
  color: rgba(31, 214, 208, 0.16);
  -webkit-text-stroke-color: var(--neon);
}
.band--tint { background: rgba(46, 158, 99, 0.08); }

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 50px;
  padding: 12px 26px;
  border: 2px solid transparent;
  border-radius: var(--r-pill);
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.01em;
  line-height: 1.1;
  text-decoration: none;
  transition: transform 0.22s var(--ease), background-color 0.22s var(--ease),
    color 0.22s var(--ease), border-color 0.22s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn--primary { background: var(--grass); color: var(--card); }
.btn--primary:hover { background: #268B55; }
.btn--clay { background: var(--clay); color: var(--card); }
.btn--clay:hover { background: var(--sun); }
.btn--ghost { background: transparent; border-color: var(--ink); color: var(--ink); }
.btn--ghost:hover { background: var(--ink); color: var(--paper); }
.btn--dark { background: var(--ink); color: var(--paper); }
.btn--dark:hover { background: var(--night); }
.band--dark .btn--ghost { border-color: var(--neon); color: var(--neon); }
.band--dark .btn--ghost:hover { background: var(--neon); color: var(--night); }
.btn--sm { min-height: 40px; padding: 8px 18px; font-size: 15px; }
.btn--block { width: 100%; }

/* ---------- 6. 标签 / 卡片 / 统计 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  background: var(--card);
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}
.tag--grass { background: rgba(46, 158, 99, 0.14); border-color: rgba(46, 158, 99, 0.5); color: #1E6E45; }
.tag--clay { background: rgba(192, 73, 42, 0.12); border-color: rgba(192, 73, 42, 0.45); color: #9C3A21; }
.tag--neon { background: rgba(31, 214, 208, 0.16); border-color: rgba(31, 214, 208, 0.55); color: #0F7E7A; }
.tag--gold { background: rgba(228, 178, 60, 0.18); border-color: rgba(228, 178, 60, 0.55); color: #8A6A12; }
.tag--stone { background: transparent; border-color: var(--line); color: var(--stone); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  padding: clamp(20px, 3vw, 32px);
  box-shadow: var(--shadow-card);
}
.card--flat { box-shadow: none; }
.card--dark {
  background: var(--night);
  border-color: rgba(31, 214, 208, 0.3);
  color: var(--card);
}
.card--dark .stat__num { color: var(--neon); }

.stat { display: grid; gap: 8px; }
.stat__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(36px, 5vw, 72px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--grass);
}
.stat__label { font-size: 14px; color: var(--ink-soft); }

/* ---------- 7. 面包屑 ---------- */
.crumb {
  padding-block: 18px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--stone);
}
.crumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.crumb li { display: flex; align-items: center; gap: 8px; }
.crumb li + li::before { content: "/"; color: var(--line); }
.crumb a { color: var(--ink-soft); text-decoration: none; }
.crumb a:hover { color: var(--clay); text-decoration: underline; }
.crumb [aria-current="page"] { color: var(--ink); }

/* ---------- 8. 网格 ---------- */
.asym {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 24px;
  align-items: start;
}
.asym__main { grid-column: span 7; min-width: 0; }
.asym__aside { grid-column: span 4; min-width: 0; }
.asym__gap { grid-column: span 1; }

.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }

/* ---------- 9. 编号章节 ---------- */
.chapter { display: grid; gap: 16px; }
.chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(56px, 9vw, 96px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: rgba(192, 73, 42, 0.14);
  -webkit-text-stroke: 2px var(--clay);
}
.chapter__title { max-width: 24ch; }
.chapter__lead { max-width: 60ch; color: var(--ink-soft); font-size: 16.5px; }

/* ---------- 10. 图片容器 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border-radius: var(--r-media);
  background: linear-gradient(140deg, #E9E1CE, #D8CFB8);
  margin: 0;
}
.media__img { width: 100%; height: 100%; object-fit: cover; }
.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--3x4 { aspect-ratio: 3 / 4; }
.media--framed { border: 2px solid var(--ink); }
.media--framed::before,
.media--framed::after {
  content: "";
  position: absolute;
  width: 26px;
  height: 26px;
  border: 2px solid var(--neon);
  pointer-events: none;
}
.media--framed::before { top: 12px; left: 12px; border-right: 0; border-bottom: 0; }
.media--framed::after { right: 12px; bottom: 12px; border-top: 0; border-left: 0; }
.media__cap {
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 14px;
  padding: 6px 14px;
  border-radius: var(--r-pill);
  background: rgba(14, 31, 25, 0.74);
  color: var(--card);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.03em;
}

/* ---------- 11. 折叠内容组 ---------- */
.acc { display: grid; gap: 10px; }
.acc__item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  overflow: hidden;
  transition: box-shadow 0.28s var(--ease), border-color 0.28s var(--ease);
}
.acc__item.is-open {
  box-shadow: inset 4px 0 0 var(--grass), var(--shadow-card);
  border-color: rgba(46, 158, 99, 0.45);
}
.acc__btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  width: 100%;
  padding: 18px 22px;
  border: 0;
  background: none;
  text-align: left;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
}
.acc__icon {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--grass);
  transition: transform 0.28s var(--ease);
}
.acc__btn[aria-expanded="true"] .acc__icon { transform: rotate(45deg); }
.acc__panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.32s var(--ease);
}
.acc__body {
  padding: 0 22px 22px;
  color: var(--ink-soft);
  font-size: 16px;
}
.acc__body > * + * { margin-top: 0.9em; }

/* ---------- 12. 表格骨架 ---------- */
.table-wrap {
  overflow: auto;
  max-height: 76vh;
  border: 1px solid var(--line);
  border-radius: var(--r-card);
  background: var(--card);
}
.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
  font-size: 16px;
}
.table-wrap th,
.table-wrap td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  white-space: nowrap;
}
.table-wrap thead th {
  position: sticky;
  top: 0;
  z-index: 2;
  background: #F1E9D8;
  color: var(--stone);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.table-wrap tbody tr:nth-child(even) { background: rgba(14, 31, 25, 0.03); }
.table-wrap tbody tr:hover { background: rgba(46, 158, 99, 0.1); }

/* ---------- 13. 头部 ---------- */
.skip-link {
  position: fixed;
  top: 8px;
  left: 50%;
  z-index: 300;
  transform: translate(-50%, -180%);
  padding: 10px 20px;
  border-radius: var(--r-pill);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.24s var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); }

.site-header {
  position: fixed;
  top: var(--frame);
  left: var(--frame);
  right: var(--frame);
  z-index: 120;
  height: var(--head-h);
  background: var(--paper);
  color: var(--ink);
  border-bottom: 2px solid var(--ink);
  transition: height 0.3s var(--ease), background-color 0.3s var(--ease),
    color 0.3s var(--ease), border-color 0.3s var(--ease);
}
.site-header.is-scrolled {
  height: 60px;
  background: var(--night);
  color: var(--card);
  border-bottom-color: rgba(31, 214, 208, 0.55);
}

.sh-bar {
  position: relative;
  display: flex;
  align-items: center;
  gap: 14px;
  width: min(1440px, 100%);
  height: 100%;
  margin-inline: auto;
  padding-inline: 18px;
}

.sh-brand {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  color: inherit;
  text-decoration: none;
}
.sh-brand-mark {
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  color: var(--grass);
  transition: color 0.3s var(--ease), transform 0.4s var(--ease);
}
.sh-brand:hover .sh-brand-mark { transform: rotate(90deg); }
.site-header.is-scrolled .sh-brand-mark { color: var(--neon); }

.sh-brand-text { display: block; line-height: 1; }
.sh-brand-text strong {
  display: block;
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.02em;
  transition: font-size 0.3s var(--ease);
}
.sh-brand-text em {
  display: block;
  margin-top: 4px;
  font-family: var(--font-mono);
  font-style: normal;
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--stone);
}
.site-header.is-scrolled .sh-brand-text strong { font-size: 19px; }
.site-header.is-scrolled .sh-brand-text em { color: var(--stone-lift); }

.sh-nav {
  flex: 1 1 auto;
  min-width: 0;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  -webkit-mask-image: linear-gradient(90deg, transparent 0, #000 16px, #000 calc(100% - 16px), transparent 100%);
  mask-image: linear-gradient(90deg, transparent 0, #000 16px, #000 calc(100% - 16px), transparent 100%);
}
.sh-nav::-webkit-scrollbar { display: none; }

.sh-track {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 16px;
}
.sh-link {
  display: inline-block;
  padding: 8px 16px;
  border-radius: var(--r-pill);
  color: inherit;
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 0.24s var(--ease), color 0.24s var(--ease), box-shadow 0.24s var(--ease);
}
.sh-link:hover { background: rgba(46, 158, 99, 0.16); }
.sh-link[aria-current="page"] {
  background: var(--grass);
  color: var(--card);
  font-weight: 700;
}
.site-header.is-scrolled .sh-link:hover { background: rgba(31, 214, 208, 0.16); }
.site-header.is-scrolled .sh-link[aria-current="page"] {
  background: var(--grass);
  color: var(--ink);
  box-shadow: 0 0 0 1px var(--neon);
}

.sh-cta {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  height: 42px;
  padding: 0 20px;
  border-radius: var(--r-pill);
  background: var(--clay);
  color: var(--card);
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.01em;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 0.24s var(--ease), transform 0.24s var(--ease);
}
.sh-cta:hover { background: var(--sun); transform: translateY(-1px); }
.site-header.is-scrolled .sh-cta { background: var(--grass); color: var(--card); }
.site-header.is-scrolled .sh-cta:hover { background: var(--sun); }

.nav-toggle {
  display: none;
  flex: 0 0 auto;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 14px;
  border: 2px solid currentColor;
  border-radius: var(--r-pill);
  background: transparent;
  color: inherit;
}
.nav-toggle-text {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
}
.nav-toggle-bars { display: grid; gap: 3px; width: 16px; }
.nav-toggle-bars i {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.24s var(--ease), opacity 0.24s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* ---------- 14. 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 1;
  background: var(--night);
  color: var(--card);
  border-top: 2px solid rgba(31, 214, 208, 0.4);
}

.sf-wrap {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr 0.9fr auto;
  gap: 40px;
  width: min(1240px, 100% - 48px);
  margin-inline: auto;
  padding: 64px 0 40px;
}

.sf-col { min-width: 0; }
.sf-col--brand { max-width: 420px; }
.sf-col--links { display: flex; flex-direction: column; }

.sf-brand {
  display: flex;
  align-items: center;
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--card);
}
.sf-brand-dot {
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-right: 10px;
  border-radius: 50%;
  background: var(--neon);
  box-shadow: 0 0 0 4px rgba(31, 214, 208, 0.18);
  animation: pulse 1.6s ease-in-out infinite;
}
.sf-tag {
  margin-top: 10px;
  font-size: 14px;
  color: var(--stone-lift);
}

.sf-meta {
  display: grid;
  gap: 8px;
  margin-top: 22px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
}
.sf-meta-row { display: flex; flex-wrap: wrap; gap: 10px; }
.sf-meta-row dt { flex: 0 0 auto; min-width: 66px; color: var(--stone); }
.sf-meta-row dd { margin: 0; color: var(--stone-lift); word-break: break-all; }

.sf-col-title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--stone-lift);
}
.sf-links a {
  display: inline-block;
  padding: 5px 0;
  color: var(--card);
  font-size: 15px;
  text-decoration: none;
  opacity: 0.82;
  transition: opacity 0.2s var(--ease), color 0.2s var(--ease);
}
.sf-links a:hover { opacity: 1; color: var(--neon); text-decoration: underline; }

.sf-dial {
  display: grid;
  gap: 10px;
  justify-items: center;
  text-align: center;
}
.sf-dial-ring {
  position: relative;
  display: grid;
  place-items: center;
  width: 112px;
  height: 112px;
  color: var(--neon);
}
.sf-dial-ring svg {
  width: 100%;
  height: 100%;
  animation: dial-spin 26s linear infinite;
}
.sf-dial-num {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 22px;
  letter-spacing: -0.02em;
  color: var(--card);
}
.sf-dial-cap { font-size: 13px; color: var(--stone-lift); }
.sf-dial-state {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--neon);
}
.sf-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--neon);
  animation: pulse 1.6s ease-in-out infinite;
}

.sf-base {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  justify-content: space-between;
  width: min(1240px, 100% - 48px);
  margin-inline: auto;
  padding: 18px 0 34px;
  border-top: 1px solid rgba(140, 136, 119, 0.3);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--stone);
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.45; transform: scale(0.82); }
}
@keyframes dial-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ---------- 15. 滚动组件 ---------- */
.scroll-progress {
  position: fixed;
  top: var(--frame);
  left: var(--frame);
  right: var(--frame);
  height: 3px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--grass), var(--neon) 62%, var(--sun));
  pointer-events: none;
  z-index: 250;
}

.to-top {
  position: fixed;
  right: 22px;
  bottom: 26px;
  z-index: 180;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border: 2px solid var(--ink);
  border-radius: var(--r-pill);
  background: var(--card);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.28s var(--ease), transform 0.28s var(--ease), visibility 0.28s linear;
}
.to-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { background: var(--grass); color: var(--card); }

/* ---------- 16. 显现协议 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}
[data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 17. 响应式 ---------- */
@media (max-width: 1180px) {
  .asym__main { grid-column: span 8; }
  .asym__aside { grid-column: span 4; }
}

@media (max-width: 960px) {
  .asym { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .asym__main,
  .asym__aside,
  .asym__gap { grid-column: span 6; }
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .sf-wrap { grid-template-columns: 1fr 1fr; gap: 36px; }
  .sf-dial { justify-items: start; text-align: left; }
}

@media (max-width: 860px) {
  .nav-toggle { display: inline-flex; }

  .sh-nav {
    position: absolute;
    top: calc(100% + 2px);
    left: 0;
    right: 0;
    display: none;
    max-height: calc(100vh - var(--head-h) - 80px);
    padding: 14px 18px 20px;
    overflow-x: hidden;
    overflow-y: auto;
    background: var(--paper);
    color: var(--ink);
    border-bottom: 2px solid var(--ink);
    box-shadow: 0 24px 40px -30px rgba(14, 31, 25, 0.7);
    -webkit-mask-image: none;
    mask-image: none;
  }
  .sh-nav[data-open="true"] { display: block; }
  .site-header.is-scrolled .sh-nav {
    background: var(--night);
    color: var(--card);
    border-bottom-color: rgba(31, 214, 208, 0.55);
  }
  .sh-track { flex-direction: column; align-items: stretch; gap: 4px; padding: 0; }
  .sh-link { display: block; padding: 13px 16px; border-radius: var(--r-sm); font-size: 17px; }
  .sh-link[aria-current="page"] { border-radius: var(--r-sm); }
  .sf-wrap { padding-top: 52px; }
}

@media (max-width: 720px) {
  :root { --head-h: 64px; }
  body { font-size: 16px; }
  .wrap,
  .wrap--narrow,
  .sf-wrap,
  .sf-base { width: calc(100% - 32px); }
  .grid-2,
  .grid-3 { grid-template-columns: 1fr; }
  .sf-wrap { grid-template-columns: 1fr; gap: 32px; }
  .sh-band { gap: 10px; }
  .sh-brand-text strong { font-size: 19px; }
  .sh-brand-mark { width: 30px; height: 30px; }
  .sh-cta { height: 38px; padding: 0 14px; font-size: 14px; }
  .chapter__num { -webkit-text-stroke-width: 1.5px; }
  .to-top { right: 14px; bottom: 16px; width: 44px; height: 44px; }
}

@media (max-width: 520px) {
  .sh-brand-text em { display: none; }
  .sh-brand-text strong { font-size: 18px; }
  .nav-toggle-text { display: none; }
  .sh-cta { padding: 0 12px; font-size: 13px; }
  .acc__btn { font-size: 18px; padding: 16px 16px; }
  .acc__body { padding: 0 16px 18px; }
}

/* ---------- 18. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  [data-reveal] {
    opacity: 1;
    transform: none;
    transition-delay: 0ms !important;
  }
  .scroll-progress { transition: none; }
}