:root {
  --color-surface: #201f21;
  --color-surface-alt: #2f2d30;
  --color-surface-deep: #403e42;
  --color-ink: #c2bac5;
  --color-ink-soft: #96899a;
  --color-ink-muted: #847788;
  --color-line: #3d3b3f;
  --color-primary: #a839cb;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #332339;
  --color-accent: #23dc64;
  --color-accent-ink: #161118;
  --color-highlight: #21412d;
  --color-focus: #16e960;
  --color-contrast-surface: #f5f4f5;
  --color-contrast-ink: #373338;
  --color-contrast-line: #cbcacb;
  --color-contrast-accent: #14803a;
  --overlay-scrim: linear-gradient(180deg, rgba(245, 244, 245, 0.35) 0%, rgba(245, 244, 245, 0.72) 55%, rgba(245, 244, 245, 0.92) 100%);
  --font-heading: STZhongsong, "Source Han Serif SC", "Songti SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, 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(39px, 8.0vw, 102px);
  --text-figure: clamp(32px, 5.7vw, 73px);
  --weight-heading: 594;
  --weight-body: 400;
  --leading-body: 1.78;
  --leading-heading: 1.18;
  --tracking-heading: 0.024em;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 9px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 6px 18px rgba(194, 186, 197, 0.08);
  --shadow-2: 0 18px 44px rgba(194, 186, 197, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1160px;
  --measure: 64ch;
  --gutter: 16px;
  --section-y: 95px;
  --section-y-lg: 133px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  background-color: var(--color-surface);
}

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; padding: 0; }

ul, ol { list-style: none; }

img, svg, picture, video { display: block; max-width: 100%; }

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%; }

:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ===== 基础排版 ===== */
body {
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  letter-spacing: 0.01em;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-wrap: balance;
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }

p { max-width: none; }

strong { font-weight: 600; color: var(--color-ink); }

::selection {
  background: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ===== 容器与分区 ===== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

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

.prose { max-width: var(--measure); }
.prose p + p { margin-top: var(--space-2); }
.prose h2 { margin-top: var(--space-6); }
.prose h3 { margin-top: var(--space-4); }
.prose ul, .prose ol { margin-top: var(--space-2); display: grid; gap: var(--space-1); }
.prose ul li { padding-left: var(--space-3); position: relative; }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: calc(var(--leading-body) * 0.5em);
  width: 12px;
  height: var(--border-thin);
  background: var(--color-primary);
}

.rule {
  height: var(--border-thin);
  width: 100%;
  background: var(--color-line);
  border: 0;
}

.scale-line {
  height: 9px;
  border-top: var(--border-thin) solid var(--color-line);
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-line) 0 var(--border-thin),
    transparent var(--border-thin) 40px
  );
  background-repeat: no-repeat;
  background-size: 100% 9px;
}

.eyebrow {
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  color: var(--color-ink-soft);
  font-family: var(--font-body);
}

.muted { color: var(--color-ink-soft); }
.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ===== 展示字号（仅首屏与大数字） ===== */
.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.02;
  letter-spacing: 0.02em;
  color: var(--color-ink);
}

.data-figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary-ink);
}

/* ===== 色块与数据组件 ===== */
.chapter-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.metric-chip {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1);
  padding: 2px var(--space-1);
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
}

.conclusion {
  background: var(--color-highlight);
  color: var(--color-ink);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-3);
}

.panel-contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
}

.panel-contrast h2,
.panel-contrast h3,
.panel-contrast h4 { color: var(--color-contrast-ink); }

.panel-contrast .rule { background: var(--color-contrast-line); }

.panel-contrast .mono,
.panel-contrast strong { color: var(--color-contrast-accent); }

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

.data-card {
  background: var(--color-surface-alt);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  box-shadow: var(--shadow-1);
  transition: box-shadow 0.25s ease, background-color 0.25s ease;
}

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

.data-card:hover {
  box-shadow: var(--shadow-2), 0 0 0 var(--border-thin) color-mix(in srgb, var(--color-primary) 45%, transparent);
}

.data-card--live {
  background: var(--color-primary-soft);
  box-shadow: inset 0 0 0 var(--border-thin) color-mix(in srgb, var(--color-accent) 42%, transparent), var(--shadow-1);
}

.data-card--live:hover {
  box-shadow: inset 0 0 0 var(--border-thin) color-mix(in srgb, var(--color-accent) 62%, transparent), var(--shadow-2);
}

.data-table {
  font-size: var(--text-base);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface-alt);
}

.data-table th {
  background: var(--color-surface-deep);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: var(--weight-body);
  letter-spacing: 0.08em;
  text-align: left;
  padding: var(--space-2) var(--space-3);
}

.data-table td {
  padding: var(--space-2) var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  color: var(--color-ink);
}

.data-table tr:last-child td { border-bottom: 0; }

.data-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

/* ===== 框景 ===== */
.frame {
  position: relative;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-6) var(--space-4);
  background: color-mix(in srgb, var(--color-surface-alt) 55%, transparent);
}

.frame::before,
.frame::after {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  pointer-events: none;
}

.frame::before {
  top: -1px;
  left: -1px;
  border-top: var(--border-thick) solid var(--color-primary);
  border-left: var(--border-thick) solid var(--color-primary);
  border-top-left-radius: var(--radius-lg);
}

.frame::after {
  right: -1px;
  bottom: -1px;
  border-bottom: var(--border-thick) solid var(--color-primary);
  border-right: var(--border-thick) solid var(--color-primary);
  border-bottom-right-radius: var(--radius-lg);
}

.frame__corner {
  position: absolute;
  width: 18px;
  height: 18px;
  pointer-events: none;
}

/* ===== 图片容器 ===== */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--color-surface-alt);
  aspect-ratio: 16 / 9;
}

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

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

.media-frame__caption {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-2);
  z-index: 2;
  color: var(--color-contrast-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  line-height: 1.4;
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }

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

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

/* ===== 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 var(--color-line);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-ink);
  background: transparent;
  transition: background-color 0.22s ease, border-color 0.22s ease, color 0.22s ease, transform 0.22s ease;
}

.btn:hover {
  background: var(--color-surface-alt);
  border-color: color-mix(in srgb, var(--color-primary) 55%, var(--color-line));
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.btn-primary:hover {
  background: color-mix(in srgb, var(--color-primary) 82%, var(--color-primary-ink));
  border-color: color-mix(in srgb, var(--color-primary) 82%, var(--color-primary-ink));
  color: var(--color-primary-ink);
}

.btn-ghost {
  border-color: color-mix(in srgb, var(--color-accent) 45%, var(--color-line));
  color: var(--color-accent);
}

.btn-ghost:hover {
  background: color-mix(in srgb, var(--color-accent) 14%, transparent);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ===== 面包屑 ===== */
.breadcrumb {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  padding-block: var(--space-3) 0;
}

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

.breadcrumb li + li::before {
  content: "/";
  margin-inline-end: var(--space-1);
  color: var(--color-line);
}

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

/* ===== 章节目录 ===== */
.chapter-rail {
  position: sticky;
  top: 132px;
  align-self: start;
  display: grid;
  gap: var(--space-2);
  padding-left: var(--space-2);
  border-left: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

.chapter-rail a {
  display: flex;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.chapter-rail a:hover { color: var(--color-ink); }

.chapter-rail a[aria-current="true"] { color: var(--color-primary); }

/* ===== 进入视口显现 ===== */
.reveal {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.34s ease, transform 0.34s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ===== 头部 ===== */
.skip-link {
  position: absolute;
  top: -80px;
  left: var(--space-2);
  z-index: 90;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
}

.skip-link:focus { top: var(--space-2); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-surface) 94%, transparent);
  backdrop-filter: blur(10px);
}

.brand-bar { padding-block: var(--space-2) var(--space-1); }

.brand-bar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.brand-cluster {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  min-width: 0;
}

.brand {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  white-space: nowrap;
}

.brand__sep {
  margin-inline: 6px;
  color: var(--color-primary);
}

.brand-note {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  white-space: nowrap;
}

.brand-tools {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
}

.season-switcher {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  max-width: 460px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
  padding-block: 2px;
}

.season-switcher::-webkit-scrollbar { display: none; }

.season-chip {
  flex: 0 0 auto;
  white-space: nowrap;
  padding: 3px 10px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
  background: transparent;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.season-chip:hover { color: var(--color-ink); }

.season-chip[aria-pressed="true"] {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
  color: var(--color-ink);
}

.brand-link {
  flex: 0 0 auto;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) solid var(--color-line);
  padding-bottom: 2px;
  white-space: nowrap;
}

.brand-link:hover { color: var(--color-accent); }

.nav-strip { border-bottom: var(--border-thin) solid var(--color-line); }

.nav-strip__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
}

.primary-nav {
  display: flex;
  align-items: center;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.nav-link {
  display: inline-block;
  padding-block: var(--space-2);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
  border-bottom: var(--border-thick) solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.nav-link:hover { color: var(--color-ink); }

.nav-link[aria-current="page"] {
  color: var(--color-ink);
  border-bottom-color: var(--color-primary);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  margin-block: var(--space-2);
  padding: 6px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  color: var(--color-ink);
}

.nav-toggle:hover { border-color: var(--color-primary); }

.nav-toggle__mark {
  width: 14px;
  height: 8px;
  border-top: var(--border-thin) solid currentColor;
  border-bottom: var(--border-thin) solid currentColor;
}

.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: var(--border-thick);
  overflow: hidden;
  pointer-events: none;
}

.scroll-progress::after {
  content: "";
  display: block;
  width: 100%;
  height: 100%;
  transform-origin: left center;
  transform: scaleX(var(--progress, 0));
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
}

/* ===== 页脚 ===== */
.site-footer {
  margin-top: var(--section-y);
  background: var(--color-surface);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-ruler {
  height: 10px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-line) 0 var(--border-thin),
    transparent var(--border-thin) 64px
  );
  background-repeat: no-repeat;
  background-size: 100% 10px;
}

.footer-ruler-labels {
  display: flex;
  justify-content: space-between;
  gap: var(--space-2);
  padding-block: var(--space-1) var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
  padding-block: var(--space-6) var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-heading {
  font-size: var(--text-sm);
  letter-spacing: 0.1em;
  color: var(--color-ink);
}

.footer-text {
  margin-top: var(--space-2);
  max-width: 32ch;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: 1.7;
}

.footer-links {
  margin-top: var(--space-2);
  display: grid;
  gap: var(--space-1);
  font-size: var(--text-sm);
}

.footer-links a {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.footer-links a:hover {
  color: var(--color-accent);
  border-bottom-color: color-mix(in srgb, var(--color-accent) 45%, transparent);
}

.footer-contact {
  margin-top: var(--space-2);
  display: grid;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: 1.6;
}

.footer-contact__value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
  padding-block: var(--space-3);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.footer-bottom p {
  max-width: none;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.footer-bottom__links {
  display: flex;
  gap: var(--space-3);
}

.footer-bottom__links a:hover { color: var(--color-ink); }

.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 45;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  min-height: 44px;
  padding: 0 var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background: color-mix(in srgb, var(--color-surface-alt) 92%, transparent);
  backdrop-filter: blur(8px);
  color: var(--color-ink);
  font-size: var(--text-sm);
  box-shadow: var(--shadow-2);
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: opacity 0.28s ease, transform 0.28s ease, border-color 0.28s ease;
}

.to-top[data-visible] {
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

.to-top:hover { border-color: var(--color-primary); }

.to-top__arrow {
  font-family: var(--font-mono);
  color: var(--color-accent);
}

/* ===== 平板 ===== */
@media (max-width: 1000px) {
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .nav-list { gap: var(--space-3); }
}

@media (max-width: 860px) {
  :root { --section-y: 64px; --section-y-lg: 80px; }

  .grid { grid-template-columns: 1fr; }
  .span-4, .span-5, .span-6, .span-7, .span-8, .span-12 { grid-column: auto; }

  .brand-bar__inner { flex-wrap: wrap; }
  .brand-note { display: none; }

  .brand-tools {
    width: 100%;
    justify-content: space-between;
    align-items: center;
  }

  .season-switcher { max-width: none; flex: 1 1 auto; }

  .nav-strip__inner { flex-wrap: wrap; padding-block: 0; }

  .nav-toggle { display: inline-flex; }

  .primary-nav { flex: 1 1 100%; }

  .nav-list {
    display: none;
    gap: var(--space-2);
    overflow-x: auto;
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
    padding-bottom: var(--space-1);
    scroll-snap-type: x proximity;
  }

  .nav-list::-webkit-scrollbar { display: none; }

  .primary-nav[data-open] .nav-list { display: flex; }

  .nav-link {
    white-space: nowrap;
    scroll-snap-align: start;
    border-bottom-color: transparent;
  }

  .chapter-rail {
    position: static;
    border-left: 0;
    padding-left: 0;
    grid-template-columns: repeat(auto-fit, minmax(96px, 1fr));
  }

  .frame { padding: var(--space-4) var(--space-3); }
}

@media (max-width: 560px) {
  .footer-grid { grid-template-columns: 1fr; }
  .footer-ruler-labels li:nth-child(even) { display: none; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
  .to-top { right: var(--space-2); bottom: var(--space-2); }
  .to-top__label { display: none; }
  .to-top { min-width: 44px; justify-content: center; padding-inline: 0; }
}

/* ===== 动效降级 ===== */
@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;
  }

  .reveal {
    opacity: 1 !important;
    transform: none !important;
  }

  .btn:hover { transform: none; }
}