/* ==========================================================================
   合乐在线 HI · 全站共享样式 /assets/site.css
   外壳：88px 侧轨导航 + 顶部状态条 + 暖纸底深墨结构线
   ========================================================================== */

/* ---------- 1. 设计变量 ---------- */
:root {
  --rail-w: 88px;
  --statusbar-h: 38px;

  --apricot: #F26B3A;
  --apricot-deep: #C64E22;
  --apricot-wash: #FDEDE6;
  --paper: #F7F1E6;
  --panel: #FFFCF7;
  --ink: #1B2A4A;
  --ink-2: #3B4C70;
  --mint: #3FC7A8;
  --mint-wash: #E4F7F1;
  --mint-ink: #1F7A66;
  --sticky: #F7C948;
  --line: #D9D2C4;
  --muted: #6B6558;
  --footer-ink: #EDE6D8;

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

  --ease: cubic-bezier(.22, .61, .36, 1);
  --radius: 2px;
}

/* ---------- 2. Reset 与基础 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--statusbar-h) + 12px);
}

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

ul, ol { padding: 0; list-style: none; }

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

button, input, select, textarea { font: inherit; color: inherit; }

a { color: inherit; }

table { border-collapse: collapse; width: 100%; }

:focus { outline: none; }

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

::selection { background: var(--apricot); color: #fff; }

body {
  min-height: 100vh;
  margin: 0;
  padding-top: var(--statusbar-h);
  padding-left: var(--rail-w);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16.5px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: .005em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

#main-content { display: block; scroll-margin-top: calc(var(--statusbar-h) + 12px); }

/* ---------- 3. 中文排版 ---------- */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.28;
  letter-spacing: -.01em;
  color: var(--ink);
}

h1 { font-size: clamp(34px, 5vw, 62px); line-height: 1.1; }
h2 { font-size: clamp(26px, 3vw, 34px); }
h3 { font-size: clamp(19px, 1.6vw, 24px); }
h4 { font-size: 18px; }

.mono {
  font-family: var(--font-mono);
  letter-spacing: .02em;
}

/* ---------- 4. 容器、网格、细线 ---------- */
.container {
  width: 100%;
  max-width: 1240px;
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 48px);
}
.container--narrow { max-width: 880px; }
.container--wide { max-width: 1440px; }

.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); }

.section { padding-block: clamp(48px, 7vw, 96px); }
.section + .section { border-top: 1px solid var(--line); }

.section-head { margin-bottom: clamp(24px, 3vw, 40px); }
.section-head__num {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .14em;
  color: var(--apricot-deep);
  text-transform: uppercase;
}
.section-head__title { margin-top: 8px; }
.section-head__desc {
  margin-top: 12px;
  max-width: 40em;
  color: var(--ink-2);
  font-size: 16px;
}

.rule { border: 0; border-top: 1px solid var(--line); margin: 0; }

.status-dot {
  display: inline-block;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--mint);
  box-shadow: 0 0 0 3px var(--mint-wash);
  vertical-align: middle;
}

/* ---------- 5. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 8px; left: 8px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--paper);
  font-size: 14px;
  text-decoration: none;
  border-radius: var(--radius);
  transform: translateY(-180%);
  transition: transform .18s var(--ease);
}
.skip-link:focus,
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 6. 顶部状态条 ---------- */
.statusbar {
  position: fixed;
  top: 0; right: 0; bottom: auto; left: var(--rail-w);
  height: var(--statusbar-h);
  z-index: 90;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 20px;
  background: rgba(247, 241, 230, .94);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  font-size: 13px;
}

.statusbar__dot {
  width: 7px; height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--mint);
  box-shadow: 0 0 0 3px var(--mint-wash);
}

.statusbar__brand {
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--ink);
  white-space: nowrap;
}

.statusbar__sep {
  width: 1px; height: 14px;
  flex: 0 0 auto;
  background: var(--line);
}

.statusbar__now {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}

.statusbar__meta {
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--muted);
  white-space: nowrap;
}

/* ---------- 7. 移动端菜单按钮 ---------- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  padding: 8px 14px;
  border: 0;
  border-radius: var(--radius);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  cursor: pointer;
  transition: background-color .18s var(--ease);
}
.nav-toggle:hover { background: var(--ink-2); }

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 14px; height: 2px;
  background: currentColor;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 14px; height: 2px;
  background: currentColor;
  transition: transform .18s var(--ease);
}
.nav-toggle__bars::before { top: -4px; }
.nav-toggle__bars::after { top: 4px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(4px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-4px) rotate(-45deg); }

/* ---------- 8. 滚动进度线 ---------- */
.scroll-progress {
  position: fixed;
  top: 0; right: 0; left: var(--rail-w);
  height: 2px;
  z-index: 130;
  background: var(--apricot);
  transform-origin: 0 50%;
  transform: scaleX(0);
  pointer-events: none;
}

/* ---------- 9. 侧轨导航 ---------- */
.rail-nav {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: var(--rail-w);
  z-index: 100;
  display: flex;
  flex-direction: column;
  padding: 16px 0 20px;
  background: var(--paper);
  border-right: 1px solid var(--line);
}

.rail-nav__caption {
  display: none;
  padding: 0 12px 10px;
  font-size: 10.5px;
  letter-spacing: .16em;
  color: var(--muted);
  text-align: center;
}

.rail__brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 7px;
  margin: 0 12px 12px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}

.rail__mark {
  display: grid;
  place-items: center;
  width: 44px; height: 44px;
  background: var(--ink);
  color: var(--paper);
  font-size: 13px;
  letter-spacing: .04em;
  border-radius: var(--radius);
}

.rail__brandtext {
  font-size: 10.5px;
  letter-spacing: .12em;
  color: var(--ink-2);
  white-space: nowrap;
}

.rail-nav__list {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 4px 10px 12px;
  scrollbar-width: thin;
  scrollbar-color: var(--line) transparent;
}
.rail-nav__list::-webkit-scrollbar { width: 4px; }
.rail-nav__list::-webkit-scrollbar-thumb { background: var(--line); }

.rail-nav__link {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 7px;
  padding: 12px 4px;
  border-radius: var(--radius);
  color: var(--ink-2);
  text-decoration: none;
  transition: background-color .18s var(--ease), color .18s var(--ease);
}

.rail-nav__link::before {
  content: "";
  position: absolute;
  left: -10px;
  top: 10px; bottom: 10px;
  width: 3px;
  background: transparent;
  transition: background-color .18s var(--ease);
}

.rail-nav__link:hover { background: var(--panel); color: var(--ink); }

.rail-nav__link[aria-current="page"] {
  background: var(--panel);
  color: var(--ink);
}
.rail-nav__link[aria-current="page"]::before { background: var(--apricot); }
.rail-nav__link[aria-current="page"] .rail-nav__num { color: var(--apricot-deep); }

.rail-nav__num {
  font-size: 10px;
  letter-spacing: .12em;
  color: var(--muted);
  line-height: 1;
}

.rail-nav__text {
  writing-mode: vertical-rl;
  text-orientation: upright;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: .18em;
  line-height: 1;
  white-space: nowrap;
}

.rail-nav__foot {
  margin-top: auto;
  padding: 12px 10px 0;
  border-top: 1px solid var(--line);
}

.rail-nav__quick {
  display: block;
  padding: 10px 6px;
  border: 1px dashed var(--mint);
  border-radius: var(--radius);
  background: var(--mint-wash);
  color: var(--mint-ink);
  font-family: var(--font-mono);
  font-size: 10.5px;
  line-height: 1.55;
  letter-spacing: .04em;
  text-align: center;
  text-decoration: none;
  word-break: break-word;
  transition: background-color .18s var(--ease);
}
.rail-nav__quick:hover { background: var(--mint); color: #062E24; }

/* ---------- 10. 返回顶部 ---------- */
.to-top {
  position: fixed;
  left: calc((var(--rail-w) - 44px) / 2);
  bottom: 22px;
  z-index: 120;
  display: grid;
  place-items: center;
  gap: 2px;
  width: 44px; height: 44px;
  padding: 0;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink);
  cursor: pointer;
  transition: background-color .18s var(--ease), color .18s var(--ease), transform .18s var(--ease);
}
.to-top[hidden] { display: none; }
.to-top:hover { background: var(--apricot); border-color: var(--apricot); color: #fff; }
.to-top:active { transform: translateY(1px); }

.to-top__arrow { font-size: 13px; line-height: 1; }
.to-top__label { font-size: 9.5px; line-height: 1; letter-spacing: .08em; }

/* ---------- 11. 页脚 ---------- */
.site-footer {
  background: var(--ink);
  color: var(--footer-ink);
  border-top: 4px solid var(--apricot);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.6fr;
  gap: clamp(24px, 3vw, 48px);
  padding-block: clamp(40px, 5vw, 64px) clamp(28px, 3.5vw, 44px);
}

.footer__brand { max-width: 34ch; }

.footer__mark {
  display: inline-block;
  padding-left: 10px;
  border-left: 3px solid var(--apricot);
  font-size: 13px;
  letter-spacing: .12em;
  color: #FFFCF7;
}

.footer__tagline {
  margin-top: 14px;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -.005em;
  color: #FFFCF7;
}

.footer__note {
  margin-top: 12px;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(237, 230, 216, .68);
}

.footer__col { min-width: 0; }

.footer__head {
  padding-bottom: 10px;
  margin-bottom: 14px;
  border-bottom: 1px solid rgba(237, 230, 216, .16);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: .14em;
  color: var(--mint);
}

.footer__list { display: grid; gap: 10px; }

.footer__link {
  font-size: 15px;
  color: var(--footer-ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.footer__link:hover { color: #fff; border-bottom-color: var(--apricot); }

.footer__list--plain li {
  font-size: 14px;
  line-height: 1.7;
  color: rgba(237, 230, 216, .88);
  word-break: break-word;
}

.footer__key {
  display: inline-block;
  min-width: 34px;
  margin-right: 8px;
  padding: 1px 6px;
  border: 1px solid rgba(237, 230, 216, .3);
  border-radius: var(--radius);
  font-size: 11px;
  color: var(--mint);
  text-align: center;
}

.footer__col--contact .footer__note { margin-top: 14px; }

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-block: 18px 26px;
  border-top: 1px solid rgba(237, 230, 216, .18);
}

.footer__line {
  font-size: 12.5px;
  letter-spacing: .06em;
  color: rgba(237, 230, 216, .78);
}
.footer__icp,
.footer__year {
  font-size: 12.5px;
  color: rgba(237, 230, 216, .58);
}

/* ---------- 12. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 22px;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color .18s var(--ease), color .18s var(--ease),
    border-color .18s var(--ease), transform .18s var(--ease);
}
.btn:hover { background: var(--ink); color: var(--paper); }
.btn:active { transform: translateY(1px); }

.btn--primary {
  background: var(--apricot);
  border-color: var(--apricot);
  color: #fff;
}
.btn--primary:hover { background: var(--apricot-deep); border-color: var(--apricot-deep); color: #fff; }

.btn--mint {
  background: var(--mint-wash);
  border-color: var(--mint);
  color: var(--mint-ink);
}
.btn--mint:hover { background: var(--mint); border-color: var(--mint); color: #062E24; }

.btn--ghost { border-color: var(--line); color: var(--ink-2); }
.btn--ghost:hover { background: var(--ink-2); border-color: var(--ink-2); color: var(--paper); }

.btn--sm { padding: 8px 14px; font-size: 13.5px; }

/* ---------- 13. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--ink-2);
  white-space: nowrap;
}
.tag--apricot { border-color: var(--apricot); background: var(--apricot-wash); color: var(--apricot-deep); }
.tag--mint { border-color: var(--mint); background: var(--mint-wash); color: var(--mint-ink); }
.tag--sticky { border-color: #E0B02E; background: #FDF4D8; color: #7A5A03; }

/* ---------- 14. 卡片 ---------- */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 22px 22px 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  transition: border-color .18s var(--ease), transform .18s var(--ease);
}
.card:hover { border-color: var(--ink); }
.card--accent { border-color: var(--apricot); box-shadow: inset 0 3px 0 var(--apricot); }

.card__cat {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--muted);
}
.card__title { font-size: 19px; font-weight: 700; letter-spacing: -.005em; }
.card__desc { font-size: 15px; color: var(--ink-2); }
.card__foot { margin-top: auto; display: flex; flex-wrap: wrap; gap: 8px; padding-top: 6px; }

/* ---------- 15. 指标卡 ---------- */
.metric {
  padding: 4px 0 4px 14px;
  border-left: 3px solid var(--apricot);
}
.metric__value {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--ink);
}
.metric__unit { margin-left: 4px; font-size: 14px; color: var(--muted); }
.metric__label { margin-top: 4px; font-size: 13.5px; color: var(--muted); }

/* ---------- 16. 勾选式清单 ---------- */
.checklist { display: grid; gap: 10px; }
.checklist__item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink-2);
}
.checklist__item::before {
  content: "";
  flex: 0 0 auto;
  width: 9px; height: 9px;
  margin-top: 9px;
  background: var(--apricot);
  transform: rotate(45deg);
}

/* ---------- 17. 注释条（原生折叠） ---------- */
.note-bar {
  border: 1px solid var(--mint);
  border-left: 3px solid var(--mint);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--mint-wash);
}
.note-bar > summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  list-style: none;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--mint-ink);
}
.note-bar > summary::-webkit-details-marker { display: none; }
.note-bar > summary::after {
  content: "＋";
  margin-left: auto;
  font-size: 14px;
  line-height: 1;
}
.note-bar[open] > summary::after { content: "－"; }
.note-bar__body {
  padding: 0 16px 16px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-2);
}
.note-bar[open] .note-bar__body { animation: noteIn .18s var(--ease) both; }

@keyframes noteIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: none; }
}

/* ---------- 18. 面包屑 ---------- */
.breadcrumb { padding-block: 14px; }
.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--muted);
}
.breadcrumb__item { display: flex; align-items: center; gap: 8px; }
.breadcrumb__item + .breadcrumb__item::before { content: "/"; color: var(--line); }
.breadcrumb__link {
  color: var(--ink-2);
  text-decoration: none;
  transition: color .18s var(--ease);
}
.breadcrumb__link:hover {
  color: var(--apricot-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.breadcrumb__current { color: var(--muted); }

/* ---------- 19. 长文正文 ---------- */
.prose {
  max-width: 40em;
  font-size: 16.8px;
  line-height: 1.8;
  color: var(--ink-2);
}
.prose > * + * { margin-top: 1.1em; }
.prose h2 { margin-top: 1.8em; font-size: 26px; }
.prose h3 { margin-top: 1.6em; font-size: 21px; }
.prose h2,
.prose h3,
.prose strong { color: var(--ink); }
.prose strong { font-weight: 700; }
.prose ul { list-style: disc; padding-left: 1.3em; }
.prose ol { list-style: decimal; padding-left: 1.3em; }
.prose li + li { margin-top: .4em; }
.prose a {
  color: var(--apricot-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.prose code {
  padding: 1px 5px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  font-family: var(--font-mono);
  font-size: .92em;
}

/* ---------- 20. 图片容器基础 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.media-frame__ratio {
  position: relative;
  overflow: hidden;
  background-color: #EFE8DA;
  background-image:
    linear-gradient(to right, rgba(27, 42, 74, .06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(27, 42, 74, .06) 1px, transparent 1px);
  background-size: 16px 16px;
}
.media-frame__ratio > img,
.media-frame__ratio > svg,
.media-frame__ratio > picture,
.media-frame__ratio > figure {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame__ratio--16x9 { aspect-ratio: 16 / 9; }
.media-frame__ratio--4x3 { aspect-ratio: 4 / 3; }
.media-frame__ratio--3x2 { aspect-ratio: 3 / 2; }
.media-frame__ratio--1x1 { aspect-ratio: 1 / 1; }

.media-frame__hint {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 16px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--muted);
  text-align: center;
}

.media-frame__caption {
  padding: 9px 14px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--muted);
}

/* ---------- 21. 滚动显现 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .5s var(--ease), transform .5s var(--ease);
}
[data-reveal][data-revealed] { opacity: 1; transform: none; }
html:not(.js) [data-reveal] { opacity: 1; transform: none; }

/* ---------- 22. 平板 ---------- */
@media (max-width: 1080px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer__brand { grid-column: 1 / -1; max-width: 46ch; }
  .footer__col--contact { grid-column: 1 / -1; }
}

/* ---------- 23. 移动端（抽屉导航） ---------- */
@media (max-width: 880px) {
  :root { --rail-w: 0px; --statusbar-h: 54px; }

  body { padding-left: 0; }

  .statusbar { padding: 0 14px; gap: 10px; }
  .statusbar__sep,
  .statusbar__meta { display: none; }
  .statusbar__brand { font-size: 11.5px; }
  .statusbar__now {
    font-size: 13px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

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

  .rail-nav {
    top: auto;
    width: auto;
    max-height: 82vh;
    flex-direction: column;
    padding: 22px 18px calc(24px + env(safe-area-inset-bottom));
    border-right: 0;
    border-top: 1px solid var(--line);
    overflow-y: auto;
    transform: translateY(102%);
    transition: transform .28s var(--ease);
    z-index: 100;
  }
  .rail-nav[data-open] { transform: translateY(0); }

  .rail-nav__caption { display: block; text-align: left; padding: 0 0 12px; }
  .rail__brand { display: none; }

  .rail-nav__list {
    flex: 0 1 auto;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    padding: 0;
    overflow: visible;
  }

  .rail-nav__link {
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    gap: 10px;
    padding: 12px 14px;
    border: 1px solid var(--line);
    background: var(--panel);
  }
  .rail-nav__link::before { display: none; }
  .rail-nav__link[aria-current="page"] {
    border-color: var(--apricot);
    background: var(--apricot-wash);
    box-shadow: inset 3px 0 0 var(--apricot);
  }

  .rail-nav__num { font-size: 11px; }
  .rail-nav__text {
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    font-size: 14.5px;
    letter-spacing: .02em;
  }

  .rail-nav__foot { margin-top: 18px; padding-top: 16px; }
  .rail-nav__quick { font-size: 12.5px; padding: 12px 10px; }

  body[data-nav-open]::after {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 95;
    background: rgba(27, 42, 74, .42);
    animation: fadeIn .18s var(--ease) both;
  }
  body[data-nav-open] .to-top { display: none; }

  .to-top { left: auto; right: 16px; bottom: 16px; }

  .scroll-progress { left: 0; }

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

  .grid--2,
  .grid--3,
  .grid--split { grid-template-columns: minmax(0, 1fr); }

  .footer__grid { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .footer__bottom { justify-content: flex-start; }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ---------- 24. 小屏微调 ---------- */
@media (max-width: 520px) {
  body { font-size: 16px; }
  .rail-nav__list { grid-template-columns: minmax(0, 1fr); }
  .statusbar__brand { display: none; }
  .statusbar__dot { display: none; }
  .metric__value { font-size: 26px; }
}

/* ---------- 25. 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  [data-reveal] { opacity: 1 !important; transform: none !important; }
  .scroll-progress { transition: none; }
}