/* =========================================================
   MANBETX 全站赛场 — /assets/site.css
   共享外壳：reset / tokens / 头部 / 页脚 / 基础组件
   ========================================================= */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
}
body { margin: 0; }
h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, pre { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video, canvas { max-width: 100%; display: block; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. Tokens ---------- */
:root {
  /* brand palette */
  --c-night: #070C16;
  --c-panel: #0E1526;
  --c-line: #1B2740;
  --c-line-strong: #2A3A5C;
  --c-body: #B7C2D4;
  --c-white: #FFFFFF;
  --c-green: #C6FF3D;
  --c-orange: #FF7A1A;
  --c-ice: #4DE1FF;
  --c-yellow: #FFD447;
  --c-muted: #8A97AE;

  /* derived surfaces */
  --s-green: rgba(198, 255, 61, .08);
  --s-green-line: rgba(198, 255, 61, .45);
  --s-orange: rgba(255, 122, 26, .10);
  --s-orange-line: rgba(255, 122, 26, .45);
  --s-ice: rgba(77, 225, 255, .08);
  --s-ice-line: rgba(77, 225, 255, .40);
  --s-yellow-line: rgba(255, 212, 71, .40);
  --s-white: rgba(255, 255, 255, .04);

  /* type */
  --font-sans: "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
               system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Roboto Mono", Menlo, Consolas,
               "Liberation Mono", "Courier New", monospace;

  /* metrics */
  --header-h: 92px;
  --shell: 1440px;
  --gutter: clamp(18px, 4vw, 48px);
  --ease: cubic-bezier(.22, .61, .36, 1);
  --radius: 6px;
  --radius-lg: 14px;

  /* fixed layer */
  --z-header: 100;
  --z-drawer: 95;
  --z-float: 80;
  --z-skip: 999;
}

/* ---------- 3. Base / 中文排版 ---------- */
body {
  background-color: var(--c-night);
  background-image:
    radial-gradient(1100px 520px at 82% -8%, rgba(77, 225, 255, .07), transparent 62%),
    radial-gradient(900px 480px at 6% 8%, rgba(198, 255, 61, .05), transparent 66%);
  background-repeat: no-repeat;
  color: var(--c-body);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: .012em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

::selection { background: var(--c-green); color: var(--c-night); }

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

strong, b { color: var(--c-white); font-weight: 700; }
em { font-style: normal; }

/* ---------- 4. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 14px;
  z-index: var(--z-skip);
  padding: 10px 20px;
  border-radius: 999px;
  background: var(--c-green);
  color: var(--c-night);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  transform: translateY(-180%);
  transition: transform .2s var(--ease);
}
.skip-link:focus { transform: translateY(0); }

/* =========================================================
   5. HEADER — 悬浮胶囊浮岛
   ========================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  padding: clamp(10px, 1.3vw, 16px) clamp(12px, 2.6vw, 30px);
  background: linear-gradient(180deg, rgba(7, 12, 22, .97) 52%, rgba(7, 12, 22, .84) 100%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.5vw, 20px);
  max-width: var(--shell);
  margin: 0 auto;
  padding: 8px 8px 8px 18px;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  background: rgba(14, 21, 38, .62);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, .045),
    0 26px 52px -38px rgba(0, 0, 0, .95);
}

/* --- brand --- */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  padding-right: 14px;
  border-right: 1px solid var(--c-line);
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: linear-gradient(140deg, var(--c-green), var(--c-ice));
  color: var(--c-night);
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 15px;
  line-height: 1;
}
.brand-copy { display: flex; flex-direction: column; line-height: 1.18; }
.brand-name {
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: .16em;
  color: var(--c-white);
}
.brand-sub {
  font-size: 11.5px;
  letter-spacing: .2em;
  color: var(--c-green);
}

/* --- nav --- */
.site-nav {
  display: flex;
  align-items: center;
  flex: 1 1 auto;
  min-width: 0;
  justify-content: center;
}
.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  min-width: 0;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.nav-list::-webkit-scrollbar { display: none; }
.nav-item { display: block; flex: 0 0 auto; }

.nav-link {
  display: block;
  white-space: nowrap;
  padding: 7px 13px;
  border: 1px solid transparent;
  border-radius: 999px;
  color: var(--c-body);
  font-size: 13.5px;
  line-height: 1.45;
  letter-spacing: .02em;
  transition: color .18s var(--ease), border-color .18s var(--ease),
              background-color .18s var(--ease);
}
.nav-link:hover {
  color: var(--c-white);
  border-color: var(--c-green);
  background: var(--s-green);
}
.nav-link[aria-current="page"] {
  color: var(--c-green);
  border-color: var(--c-green);
  background: var(--s-green);
  font-weight: 700;
}

.nav-foot { display: none; }
.nav-note {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--c-line);
  font-size: 12px;
  line-height: 1.6;
  color: var(--c-muted);
}

/* --- actions --- */
.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

/* --- toggle --- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  padding: 8px 15px;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  color: var(--c-body);
  font-size: 12.5px;
  letter-spacing: .12em;
  transition: border-color .18s var(--ease), color .18s var(--ease);
}
.nav-toggle:hover { border-color: var(--c-green); color: var(--c-green); }
.nav-toggle-lines {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}
.nav-toggle-lines i {
  position: absolute;
  left: 0;
  width: 100%;
  height: 1.5px;
  border-radius: 2px;
  background: currentColor;
  transition: top .2s var(--ease), transform .2s var(--ease);
}
.nav-toggle-lines i:first-child { top: 1px; }
.nav-toggle-lines i:last-child { top: 7px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-lines i:first-child { top: 4px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-lines i:last-child { top: 4px; transform: rotate(-45deg); }

/* --- progress --- */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  pointer-events: none;
  overflow: hidden;
}
.scroll-progress span {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--c-green), var(--c-ice) 55%, var(--c-orange));
  will-change: transform;
}

/* =========================================================
   6. FOOTER — 档案室台账
   ========================================================= */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  border-top: 1px solid var(--c-line);
  background: linear-gradient(180deg, rgba(14, 21, 38, .92), rgba(7, 12, 22, .98));
  color: var(--c-body);
  overflow: hidden;
}
.footer-glow {
  position: absolute;
  top: -260px;
  left: -12%;
  width: 60%;
  height: 460px;
  border-radius: 50%;
  background: radial-gradient(closest-side, rgba(198, 255, 61, .11), transparent 72%);
  pointer-events: none;
}

.footer-inner {
  position: relative;
  max-width: var(--shell);
  margin: 0 auto;
  padding: clamp(44px, 6vw, 84px) var(--gutter) 30px;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(260px, 1fr) minmax(0, 2.05fr);
  gap: clamp(28px, 4vw, 64px);
  padding-bottom: clamp(32px, 4vw, 56px);
  border-bottom: 1px solid var(--c-line);
}

.footer-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .24em;
  color: var(--c-orange);
  text-transform: uppercase;
}
.footer-brandline {
  margin-top: 12px;
  font-size: clamp(1.35rem, 2.6vw, 1.9rem);
  font-weight: 300;
  letter-spacing: -.01em;
  line-height: 1.2;
  color: var(--c-white);
}
.footer-intro {
  margin-top: 14px;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-muted);
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(20px, 2.4vw, 34px);
}
.footer-col-title {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 14px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--c-white);
}
.footer-col-num {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--c-orange);
}
.footer-list { display: flex; flex-direction: column; gap: 4px; }

.footer-link {
  position: relative;
  display: inline-block;
  padding: 3px 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--c-body);
  transition: color .18s var(--ease);
}
.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 1px;
  width: 100%;
  height: 1px;
  background: var(--c-green);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .2s var(--ease);
}
.footer-link:hover { color: var(--c-white); }
.footer-link:hover::after { transform: scaleX(1); }
.footer-link[aria-current="page"] { color: var(--c-green); }
.footer-link[aria-current="page"]::after { transform: scaleX(1); }

.footer-contact {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 34px);
  padding: clamp(24px, 3vw, 38px) 0;
  border-bottom: 1px solid var(--c-line);
}
.contact-row { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.contact-key {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--c-muted);
  text-transform: uppercase;
}
.contact-val {
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-white);
  word-break: break-word;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-top: 22px;
}
.footer-service {
  font-size: 12.5px;
  color: var(--c-muted);
}
.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  letter-spacing: .03em;
  color: var(--c-muted);
}
.footer-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--c-orange);
}

/* --- back to top float --- */
.to-top {
  position: fixed;
  right: clamp(14px, 2.6vw, 32px);
  bottom: clamp(14px, 2.6vw, 32px);
  z-index: var(--z-float);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 17px;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  background: rgba(14, 21, 38, .9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: var(--c-body);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .22s var(--ease), transform .22s var(--ease),
              visibility .22s, color .22s var(--ease), border-color .22s var(--ease);
}
.to-top[data-visible="true"] { opacity: 1; visibility: visible; transform: translateY(0); }
.to-top:hover { color: var(--c-green); border-color: var(--c-green); }
.to-top-arrow { font-size: 14px; line-height: 1; color: var(--c-green); }
.to-top:hover .to-top-arrow { color: var(--c-orange); }

/* =========================================================
   7. 通用组件
   ========================================================= */

/* --- layout --- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}
.shell--narrow { max-width: 980px; }

.grid { display: grid; gap: clamp(16px, 2.2vw, 28px); }
.grid--halves { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--thirds { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--quarters { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* --- sidebar chapter rail（宽屏长文索引带） --- */
.chapter-rail {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.chapter-rail a {
  display: block;
  padding: 8px 10px 8px 15px;
  border-left: 1px solid var(--c-line);
  font-size: 12.5px;
  letter-spacing: .05em;
  color: var(--c-muted);
  transition: color .18s var(--ease), border-color .18s var(--ease), padding-left .18s var(--ease);
}
.chapter-rail a:hover { color: var(--c-white); border-left-color: var(--c-line-strong); }
.chapter-rail a[aria-current="true"] {
  color: var(--c-green);
  border-left-color: var(--c-green);
  padding-left: 20px;
}

/* --- typography --- */
.display {
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: clamp(2.6rem, 7vw, 6.4rem);
  line-height: .98;
  letter-spacing: -.025em;
  color: var(--c-white);
}
.headline {
  font-size: clamp(1.45rem, 3.1vw, 2.5rem);
  font-weight: 600;
  line-height: 1.22;
  letter-spacing: -.012em;
  color: var(--c-white);
}
.index-num {
  font-family: var(--font-mono);
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .16em;
  color: var(--c-orange);
  text-transform: uppercase;
}
.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .22em;
  color: var(--c-ice);
  text-transform: uppercase;
}
.lead {
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  line-height: 1.75;
  color: var(--c-body);
}
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--c-line);
}

/* --- breadcrumb --- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  letter-spacing: .03em;
  color: var(--c-muted);
}
.breadcrumb a { color: var(--c-ice); transition: color .18s var(--ease); }
.breadcrumb a:hover { color: var(--c-green); }
.breadcrumb .crumb-sep { color: var(--c-line-strong); }
.breadcrumb [aria-current="page"] { color: var(--c-white); }

/* --- buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 21px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: .02em;
  white-space: nowrap;
  transition: color .18s var(--ease), background-color .18s var(--ease),
              border-color .18s var(--ease), transform .18s var(--ease);
}
.btn-sm { padding: 7px 15px; font-size: 13px; }
.btn-primary {
  background: var(--c-green);
  border-color: var(--c-green);
  color: var(--c-night);
  font-weight: 700;
}
.btn-primary:hover { background: #D8FF70; border-color: #D8FF70; }
.btn-ghost {
  background: var(--s-white);
  border-color: var(--c-line);
  color: var(--c-white);
}
.btn-ghost:hover { border-color: var(--c-orange); color: var(--c-orange); }
.btn:active { transform: translateY(1px); }

/* --- chips --- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 15px;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  background: transparent;
  color: var(--c-muted);
  font-size: 12.5px;
  letter-spacing: .05em;
  transition: color .18s var(--ease), border-color .18s var(--ease), background-color .18s var(--ease);
}
.chip:hover { color: var(--c-white); border-color: var(--c-line-strong); }
.chip[aria-pressed="true"] {
  color: var(--c-green);
  border-color: var(--c-green);
  background: var(--s-green);
  font-weight: 600;
}

/* --- tags --- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--c-muted);
  text-transform: uppercase;
}
.tag--green { color: var(--c-green); border-color: var(--s-green-line); }
.tag--orange { color: var(--c-orange); border-color: var(--s-orange-line); }
.tag--ice { color: var(--c-ice); border-color: var(--s-ice-line); }
.tag--yellow { color: var(--c-yellow); border-color: var(--s-yellow-line); }

/* --- card / 档案卡 --- */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(16px, 2vw, 22px);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(14, 21, 38, .9), rgba(14, 21, 38, .62));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .03);
  transition: transform .18s var(--ease), border-color .18s var(--ease), background-color .18s var(--ease);
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--c-green);
  background: linear-gradient(180deg, rgba(20, 30, 52, .95), rgba(14, 21, 38, .7));
}
.card-code {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .16em;
  color: var(--c-orange);
  text-transform: uppercase;
}
.card-title {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--c-white);
}
.card-text {
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--c-muted);
}

/* --- media 图片容器 --- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(27, 39, 64, .92), rgba(7, 12, 22, .96));
}
.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: brightness(.65) saturate(1.08) contrast(1.03);
}
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(200deg, rgba(7, 12, 22, 0) 22%, rgba(7, 12, 22, .92) 100%),
    linear-gradient(125deg, rgba(77, 225, 255, .10), transparent 48%);
}
.media--ratio-16-9 { aspect-ratio: 16 / 9; }
.media--ratio-4-3 { aspect-ratio: 4 / 3; }
.media--ratio-3-2 { aspect-ratio: 3 / 2; }
.media--ratio-1-1 { aspect-ratio: 1 / 1; }

/* --- prose 长文 --- */
.prose {
  max-width: 68ch;
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--c-body);
}
.prose > * + * { margin-top: 1.05em; }
.prose h2 {
  margin-top: 2em;
  font-size: clamp(1.3rem, 2.4vw, 1.75rem);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -.01em;
  color: var(--c-white);
}
.prose h3 {
  margin-top: 1.7em;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--c-white);
}
.prose a {
  color: var(--c-ice);
  border-bottom: 1px solid var(--s-ice-line);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.prose a:hover { color: var(--c-green); border-bottom-color: var(--c-green); }
.prose ul, .prose ol { padding-left: 1.25em; }
.prose ul li { list-style: none; position: relative; padding-left: 14px; }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 6px;
  height: 1.5px;
  background: var(--c-orange);
}
.prose ol { list-style: decimal; }
.prose code {
  font-family: var(--font-mono);
  font-size: .88em;
  padding: 2px 7px;
  border: 1px solid var(--c-line);
  border-radius: 4px;
  background: var(--c-panel);
  color: var(--c-green);
}
.prose hr { border: 0; border-top: 1px solid var(--c-line); margin: 2em 0; }
.prose blockquote {
  padding: 4px 0 4px 20px;
  border-left: 2px solid var(--c-green);
  color: var(--c-white);
  font-size: 1.02em;
}

/* --- stat / 数据带基础件 --- */
.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 0;
  border-top: 1px solid var(--c-line);
}
.stat-value {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1;
  color: var(--c-green);
}
.stat-label {
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--c-muted);
}

/* =========================================================
   8. 响应式
   ========================================================= */

/* 平板：收紧头部右侧动作区 */
@media (max-width: 1340px) {
  .header-actions .btn-ghost { display: none; }
}

/* 抽屉导航断点 */
@media (max-width: 1120px) {
  :root { --header-h: 78px; }

  .header-actions { display: none; }
  .nav-toggle { display: inline-flex; }

  .header-inner { padding: 8px; }

  .brand { padding-right: 0; border-right: 0; margin-right: auto; }

  .site-nav {
    position: fixed;
    top: calc(var(--header-h) + 4px);
    left: clamp(12px, 3vw, 24px);
    right: clamp(12px, 3vw, 24px);
    z-index: var(--z-drawer);
    display: block;
    max-height: calc(100vh - var(--header-h) - 32px);
    overflow-y: auto;
    padding: 14px;
    border: 1px solid var(--c-line);
    border-radius: 18px;
    background: rgba(14, 21, 38, .97);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    box-shadow: 0 34px 66px -34px rgba(0, 0, 0, .96);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s;
  }
  .site-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    overflow: visible;
  }
  .nav-link {
    padding: 12px 14px;
    border-radius: 11px;
    font-size: 15px;
  }

  .nav-foot {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 12px;
  }
  .nav-foot .btn { width: 100%; }

  .footer-top { grid-template-columns: minmax(0, 1fr); }
  .footer-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 26px 20px; }
  .footer-contact { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 1023px) {
  .grid--thirds, .grid--quarters { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .chapter-rail { display: none; }
}

/* 手机 */
@media (max-width: 640px) {
  body { font-size: 17px; line-height: 1.75; }
  :root { --header-h: 74px; }

  .brand-sub { display: none; }
  .brand-mark { width: 30px; height: 30px; font-size: 14px; }
  .nav-toggle-label { display: none; }
  .nav-toggle { padding: 9px 13px; }

  .grid--halves, .grid--thirds, .grid--quarters { grid-template-columns: minmax(0, 1fr); }

  .footer-nav { grid-template-columns: minmax(0, 1fr); gap: 24px; }
  .footer-contact { grid-template-columns: minmax(0, 1fr); }
  .footer-base { flex-direction: column; align-items: flex-start; }

  .to-top { padding: 9px 14px; font-size: 11.5px; letter-spacing: .06em; }
}

/* =========================================================
   9. 动效降级
   ========================================================= */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  .card:hover { transform: none; }
  .btn:active { transform: none; }
  .site-nav { transform: none; }
  .to-top { transform: none; }
  .scroll-progress span { transition: none; }
}