/* =========================================================
   AB游艺 · 共享外壳样式 /assets/site.css
   01 reset  02 变量  03 基础排版  04 通用组件
   05 头部   06 导航  07 页脚  08 响应式  09 动效偏好
   ========================================================= */

/* ---------- 01 reset ---------- */
*,
*::before,
*::after{box-sizing:border-box;}
html{
  -webkit-text-size-adjust:100%;
  background:#0B0E14;
  scroll-padding-top:132px;
}
@media (prefers-reduced-motion: no-preference){
  html{scroll-behavior:smooth;}
}
body,h1,h2,h3,h4,h5,p,figure,blockquote,dl,dd,ul,ol{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg,picture,video{display:block;max-width:100%;}
button,input,select,textarea{font:inherit;color:inherit;}
a{color:inherit;}
table{width:100%;border-collapse:collapse;}
::selection{background:#FF2D95;color:#0B0E14;}

/* ---------- 02 变量 ---------- */
:root{
  --ink:#0B0E14;
  --panel:#171A2B;
  --cyan:#00E5FF;
  --magenta:#FF2D95;
  --lime:#B6FF3B;
  --amber:#FFB300;
  --text:#E8EDF5;
  --gray:#8A94A6;
  --cream:#F4EFE6;
  --cream-ink:#14181F;
  --teal:#0E3B3E;

  --accent:var(--cyan);
  --accent-soft:rgba(0,229,255,.12);

  --rule:rgba(232,237,245,.14);
  --rule-soft:rgba(232,237,245,.08);
  --rule-strong:rgba(232,237,245,.26);

  --font-display:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,sans-serif;
  --font-serif:"Songti SC","Noto Serif SC","Source Han Serif SC",Georgia,"Times New Roman",serif;
  --font-mono:"JetBrains Mono","SFMono-Regular","SF Mono",Menlo,Consolas,"Noto Sans Mono","Courier New",monospace;

  --fs-1:clamp(2.125rem,1.46rem + 2.72vw,3.5rem);
  --fs-2:clamp(1.75rem,1.36rem + 1.6vw,2.5rem);
  --fs-3:clamp(1.375rem,1.24rem + .56vw,1.75rem);
  --fs-4:clamp(1.125rem,1.06rem + .28vw,1.25rem);
  --fs-5:clamp(1rem,.97rem + .16vw,1.0625rem);
  --fs-6:.875rem;

  --gutter:clamp(20px,5vw,64px);
  --stack:clamp(20px,3vw,36px);
}
html[data-face="b"]{
  --accent:var(--magenta);
  --accent-soft:rgba(255,45,149,.14);
}

/* ---------- 03 基础排版 ---------- */
body{
  min-height:100vh;
  background:var(--ink);
  color:var(--text);
  font-family:var(--font-body);
  font-size:var(--fs-5);
  line-height:1.8;
  letter-spacing:.01em;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(232,237,245,.05) 1px,transparent 1px),
    linear-gradient(90deg,rgba(232,237,245,.05) 1px,transparent 1px);
  background-size:72px 72px,72px 72px;
  -webkit-mask-image:radial-gradient(130% 78% at 50% 0%,#000 0%,rgba(0,0,0,.35) 58%,transparent 88%);
  mask-image:radial-gradient(130% 78% at 50% 0%,#000 0%,rgba(0,0,0,.35) 58%,transparent 88%);
}
.site-header,.site-footer,main{position:relative;z-index:1;}
h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:800;
  line-height:1.06;
  letter-spacing:-.02em;
  text-wrap:balance;
}
h1{font-size:var(--fs-1);}
h2{font-size:var(--fs-2);}
h3{font-size:var(--fs-3);line-height:1.2;}
h4{font-size:var(--fs-4);line-height:1.32;letter-spacing:-.01em;}
p{max-width:68ch;}
strong{font-weight:800;color:#fff;}
a{text-underline-offset:.22em;text-decoration-color:rgba(232,237,245,.34);}
:focus-visible{outline:2px solid var(--lime);outline-offset:3px;}

/* ---------- 04 通用组件 ---------- */
.shell{
  width:100%;
  max-width:1320px;
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.mono{
  font-family:var(--font-mono);
  letter-spacing:.04em;
  font-variant-numeric:tabular-nums;
}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.6;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--gray);
}
.eyebrow::before{
  content:"";
  width:24px;
  height:1px;
  flex:0 0 auto;
  background:linear-gradient(90deg,var(--cyan),var(--magenta));
}
.lede{
  font-family:var(--font-serif);
  font-size:calc(var(--fs-5) + 5px);
  line-height:1.7;
  letter-spacing:0;
  color:#F2F5FA;
  max-width:40ch;
}
.section-head{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(0,.76fr);
  gap:clamp(12px,3vw,48px);
  align-items:end;
  padding-bottom:16px;
  border-bottom:1px solid var(--rule);
  margin-bottom:var(--stack);
}
.section-head__title{font-size:var(--fs-2);}
.section-head__note{
  justify-self:end;
  text-align:right;
  max-width:40ch;
  font-size:var(--fs-6);
  color:var(--gray);
  line-height:1.75;
}
.rule{
  height:1px;
  border:0;
  margin-block:clamp(24px,4vw,48px);
  background:linear-gradient(90deg,var(--rule-strong),var(--rule) 40%,transparent);
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:2px 9px;
  border:1px solid currentColor;
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.7;
  letter-spacing:.08em;
  color:var(--gray);
  white-space:nowrap;
}
.tag::before{
  content:"";
  width:5px;
  height:5px;
  flex:0 0 auto;
  background:currentColor;
}
.tag--a{color:var(--cyan);}
.tag--b{color:var(--magenta);}
.tag--fresh{color:var(--lime);}
.tag--legacy{color:var(--amber);}

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  min-height:44px;
  padding:10px 20px;
  border:1px solid var(--rule-strong);
  border-radius:1px;
  background:transparent;
  color:var(--text);
  font-family:var(--font-display);
  font-size:var(--fs-6);
  font-weight:700;
  letter-spacing:.02em;
  line-height:1.4;
  text-decoration:none;
  cursor:pointer;
  transition:background-color .18s ease,color .18s ease,border-color .18s ease,transform .18s ease;
}
.btn:hover{transform:translateY(-2px);}
.btn--solid{
  border-color:var(--accent);
  background:var(--accent);
  color:#06080D;
}
.btn--solid:hover{background:transparent;color:var(--accent);}
.btn--ghost{
  border-color:var(--rule-strong);
  background:transparent;
  color:var(--text);
}
.btn--ghost:hover{
  border-color:var(--accent);
  color:var(--accent);
}
.btn--split{
  border:1px solid transparent;
  color:var(--text);
  background:
    linear-gradient(var(--panel),var(--panel)) padding-box,
    linear-gradient(90deg,var(--cyan),var(--magenta)) border-box;
}
.btn--split:hover{
  color:#fff;
  background:
    linear-gradient(90deg,rgba(0,229,255,.16),rgba(255,45,149,.18)) padding-box,
    linear-gradient(90deg,var(--cyan),var(--magenta)) border-box;
}

.grid{
  display:grid;
  gap:clamp(14px,2vw,26px);
}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid--cards{grid-template-columns:repeat(12,minmax(0,1fr));}
.grid--cards > *{grid-column:span 4;}

.card{
  position:relative;
  display:flex;
  flex-direction:column;
  gap:10px;
  padding:clamp(18px,2.4vw,28px);
  background:rgba(23,26,43,.72);
  border:1px solid var(--rule);
  transition:border-color .18s ease,transform .18s ease;
}
.card:hover,
.card:focus-within{
  border-color:var(--rule-strong);
  transform:translateY(-2px);
}
.card__kicker{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--gray);
}
.card__title{
  font-family:var(--font-display);
  font-size:var(--fs-4);
  font-weight:800;
  line-height:1.3;
  letter-spacing:-.01em;
}
.card__body{
  font-size:var(--fs-6);
  line-height:1.75;
  color:var(--gray);
}

.panel{
  padding:clamp(20px,3vw,36px);
  background:var(--panel);
  border:1px solid var(--rule);
}
.panel--teal{
  background:var(--teal);
  border-color:rgba(232,237,245,.18);
}
.panel--cream{
  background:var(--cream);
  color:var(--cream-ink);
  border-color:rgba(20,24,31,.14);
}
.panel--cream h2,.panel--cream h3,.panel--cream h4{color:var(--cream-ink);}

.split-zone{
  position:relative;
  display:grid;
  grid-template-columns:1fr 1fr;
  overflow:hidden;
  background:var(--panel);
  border:1px solid var(--rule);
}
.split-zone::after{
  content:"";
  position:absolute;
  top:-12%;
  bottom:-12%;
  left:50%;
  width:2px;
  background:linear-gradient(180deg,var(--cyan),var(--magenta));
  transform:rotate(11deg);
  opacity:.85;
}
.split-zone__a,
.split-zone__b{
  display:flex;
  flex-direction:column;
  justify-content:flex-end;
  gap:8px;
  padding:clamp(18px,3vw,36px);
}
.split-zone__a{background:linear-gradient(180deg,rgba(0,229,255,.16),rgba(0,229,255,.03));}
.split-zone__b{background:linear-gradient(180deg,rgba(255,45,149,.16),rgba(255,45,149,.03));}

.breadcrumb{margin-block:clamp(16px,3vw,28px) 0;}
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--gray);
}
.breadcrumb__list li{display:flex;align-items:center;gap:8px;}
.breadcrumb__list li + li::before{
  content:"/";
  color:rgba(232,237,245,.28);
}
.breadcrumb a{color:var(--gray);text-decoration:none;transition:color .18s ease;}
.breadcrumb a:hover{color:var(--text);}
.breadcrumb [aria-current="page"]{color:var(--text);}

.ledger{
  display:flex;
  flex-direction:column;
  border-top:1px solid var(--rule);
}
.ledger__row{
  display:grid;
  grid-template-columns:132px minmax(0,1fr) auto;
  gap:16px;
  align-items:baseline;
  padding:14px 6px;
  border-bottom:1px solid var(--rule-soft);
  text-decoration:none;
  color:inherit;
  transition:background-color .18s ease,padding-left .18s ease;
}
.ledger__row:hover{background:rgba(232,237,245,.04);padding-left:14px;}
.ledger__ver{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
  color:var(--accent);
  white-space:nowrap;
}
.ledger__meta{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
  color:var(--gray);
  white-space:nowrap;
}

.prose{max-width:68ch;}
.prose > * + *{margin-top:1.1em;}
.prose h2{margin-top:2.1em;font-size:var(--fs-3);}
.prose h3{margin-top:1.8em;font-size:var(--fs-4);}
.prose ul{list-style:none;}
.prose ul > li{position:relative;padding-left:1.2em;}
.prose ul > li + li{margin-top:.5em;}
.prose ul > li::before{
  content:"";
  position:absolute;
  left:0;
  top:.72em;
  width:6px;
  height:1px;
  background:var(--accent);
}
.prose a{color:var(--cyan);}

.toc{
  position:sticky;
  top:132px;
  font-size:var(--fs-6);
}
.toc__title{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  color:var(--gray);
  padding-bottom:10px;
  border-bottom:1px solid var(--rule-soft);
  margin-bottom:10px;
}
.toc__list{
  display:flex;
  flex-direction:column;
  gap:2px;
  border-left:1px solid var(--rule);
}
.toc__list a{
  display:block;
  padding:7px 0 7px 14px;
  margin-left:-1px;
  border-left:2px solid transparent;
  color:var(--gray);
  text-decoration:none;
  line-height:1.6;
  transition:color .18s ease,border-color .18s ease;
}
.toc__list a:hover{color:var(--text);}
.toc__list a[aria-current="true"]{
  color:var(--text);
  border-left-color:var(--accent);
}

.media{
  position:relative;
  overflow:hidden;
  aspect-ratio:16 / 10;
  border:1px solid var(--rule);
  background:
    linear-gradient(135deg,rgba(0,229,255,.12),rgba(255,45,149,.12)),
    var(--panel);
}
.media > img,
.media > svg,
.media > picture > img,
.media > video{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media--wide{aspect-ratio:21 / 9;}
.media--tall{aspect-ratio:4 / 5;}
.media--square{aspect-ratio:1 / 1;}
.media--ph::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(232,237,245,.07) 1px,transparent 1px),
    linear-gradient(90deg,rgba(232,237,245,.07) 1px,transparent 1px);
  background-size:34px 34px;
}
.media__label{
  position:absolute;
  left:12px;
  bottom:10px;
  z-index:1;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:rgba(232,237,245,.72);
}
.media__caption{
  margin-top:8px;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
  color:var(--gray);
}

[data-reveal]{
  transition:opacity .45s ease,transform .45s ease;
}
.has-js [data-reveal]{
  opacity:0;
  transform:translateY(12px);
}
.has-js [data-reveal].is-visible{
  opacity:1;
  transform:none;
}

/* ---------- 05 头部 ---------- */
.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:300;
  padding:10px 18px;
  background:var(--lime);
  color:#06080D;
  font-weight:800;
  font-size:var(--fs-6);
  text-decoration:none;
  border-radius:1px;
  transform:translateY(-180%);
  transition:transform .18s ease;
}
.skip-link:focus{transform:translateY(0);}

.site-header{
  position:sticky;
  top:0;
  z-index:100;
  background:#0B0E14;
  border-bottom:1px solid var(--rule);
  transition:box-shadow .2s ease,border-color .2s ease;
}
.site-header[data-stuck]{
  border-bottom-color:var(--rule-strong);
  box-shadow:0 14px 36px rgba(0,0,0,.5);
}
.header-rail__inner{
  display:flex;
  align-items:center;
  gap:clamp(10px,1.6vw,22px);
  min-height:74px;
  padding-block:11px;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:12px;
  min-width:0;
  text-decoration:none;
  color:inherit;
}
.brand__mark{
  position:relative;
  flex:0 0 auto;
  width:44px;
  height:44px;
  background:var(--panel);
  border:1px solid var(--rule-strong);
  overflow:hidden;
}
.brand__mark::after{
  content:"";
  position:absolute;
  inset:-24%;
  background:linear-gradient(135deg,
    transparent 48.4%,
    var(--cyan) 48.4%,
    var(--magenta) 51.6%,
    transparent 51.6%);
  opacity:.9;
}
.brand__a,
.brand__b{
  position:absolute;
  z-index:1;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:700;
  line-height:1;
  letter-spacing:.06em;
}
.brand__a{top:5px;left:6px;color:var(--cyan);}
.brand__b{bottom:5px;right:6px;color:var(--magenta);}
.brand__text{
  display:flex;
  flex-direction:column;
  gap:1px;
  min-width:0;
}
.brand__name{
  font-family:var(--font-display);
  font-size:1.125rem;
  font-weight:800;
  line-height:1.15;
  letter-spacing:-.01em;
  color:var(--text);
}
.brand__tag{
  font-family:var(--font-mono);
  font-size:10.5px;
  line-height:1.5;
  letter-spacing:.08em;
  color:var(--gray);
  white-space:nowrap;
}
.header-util{
  margin-left:auto;
  font-family:var(--font-mono);
  font-size:11.5px;
  line-height:1.6;
  letter-spacing:.08em;
  color:var(--gray);
  white-space:nowrap;
}

.face-switch{
  display:inline-flex;
  align-items:stretch;
  gap:2px;
  padding:3px;
  background:rgba(11,14,20,.72);
  border:1px solid var(--rule-strong);
}
.face-switch__btn{
  appearance:none;
  -webkit-appearance:none;
  border:0;
  background:transparent;
  color:var(--gray);
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:700;
  letter-spacing:.08em;
  line-height:1.4;
  padding:7px 11px;
  white-space:nowrap;
  cursor:pointer;
  transition:color .18s ease,background-color .18s ease;
}
.face-switch__btn:hover{
  color:var(--text);
  background:rgba(232,237,245,.07);
}
.face-switch__btn[aria-pressed="true"]{
  background:var(--accent);
  color:#06080D;
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:8px;
  min-height:40px;
  padding:8px 12px;
  background:var(--panel);
  border:1px solid var(--rule-strong);
  color:var(--text);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.1em;
  cursor:pointer;
}
.nav-toggle__bars{
  display:flex;
  flex-direction:column;
  justify-content:center;
  gap:4px;
  width:16px;
  height:12px;
}
.nav-toggle__bars i{
  display:block;
  height:1px;
  background:currentColor;
  transition:transform .2s ease,opacity .2s ease;
}
.nav-toggle[aria-expanded="true"]{
  border-color:var(--accent);
  color:var(--accent);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:first-child{
  transform:translateY(2.5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:last-child{
  transform:translateY(-2.5px) rotate(-45deg);
}

.header-deck{
  border-top:1px solid var(--rule-soft);
  background:linear-gradient(90deg,rgba(0,229,255,.07),rgba(11,14,20,0) 42%,rgba(255,45,149,.07));
}
.header-deck__inner{
  display:flex;
  align-items:center;
  min-height:54px;
}

/* ---------- 06 导航 ---------- */
.site-nav{
  display:flex;
  align-items:center;
  gap:clamp(8px,2vw,24px);
  flex:1;
  min-width:0;
}
.site-nav__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:clamp(2px,1vw,6px);
}
.site-nav__list a{
  display:inline-flex;
  align-items:baseline;
  gap:7px;
  padding:13px 11px;
  border-bottom:2px solid transparent;
  color:var(--gray);
  font-size:.9375rem;
  letter-spacing:.02em;
  text-decoration:none;
  white-space:nowrap;
  transition:color .18s ease,border-color .18s ease,background-color .18s ease;
}
.site-nav__list a:hover{
  color:var(--text);
  border-bottom-color:var(--rule-strong);
  background:rgba(232,237,245,.04);
}
.site-nav__list a[aria-current="page"]{
  color:var(--text);
  border-bottom-color:var(--accent);
}
.site-nav__idx{
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.08em;
  color:var(--gray);
  opacity:.65;
}
.site-nav__list a[aria-current="page"] .site-nav__idx{
  color:var(--accent);
  opacity:1;
}
.site-nav__cta{
  margin-left:auto;
  min-height:36px;
  padding:6px 16px;
  font-size:.8125rem;
  white-space:nowrap;
}
.site-nav__cta:hover{transform:none;}

.nav-scrim{display:none;}

.progress{
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  z-index:2;
  height:2px;
  background:rgba(232,237,245,.1);
}
.progress__bar{
  display:block;
  width:0;
  height:100%;
  background:linear-gradient(90deg,var(--cyan),var(--magenta));
  transition:width .1s linear;
}

/* ---------- 07 页脚 ---------- */
.site-footer{
  margin-top:clamp(56px,9vw,120px);
  background:linear-gradient(180deg,rgba(23,26,43,.92),rgba(11,14,20,1));
  border-top:1px solid var(--rule);
}
.site-footer::before{
  content:"";
  display:block;
  height:1px;
  background:linear-gradient(90deg,var(--cyan),var(--magenta) 58%,var(--amber));
  opacity:.72;
}
.footer-top{
  display:grid;
  grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);
  gap:clamp(28px,5vw,72px);
  padding-block:clamp(36px,6vw,68px);
  border-bottom:1px solid var(--rule-soft);
}
.footer-brand__line{
  font-family:var(--font-display);
  font-size:var(--fs-3);
  font-weight:800;
  line-height:1.2;
  letter-spacing:-.01em;
}
.footer-brand__summary{
  margin-top:12px;
  max-width:34ch;
  font-size:var(--fs-5);
  color:var(--gray);
  line-height:1.75;
}
.footer-brand .btn{margin-top:22px;}
.footer-cols{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:clamp(20px,4vw,48px);
}
.footer-col__title{
  padding-bottom:10px;
  margin-bottom:14px;
  border-bottom:1px solid var(--rule-soft);
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:700;
  letter-spacing:.16em;
  color:var(--gray);
  text-transform:uppercase;
}
.footer-col li + li{margin-top:10px;}
.footer-col a{
  display:inline-block;
  font-size:.9375rem;
  color:var(--text);
  text-decoration:none;
  transition:color .18s ease,transform .18s ease;
}
.footer-col a:hover{
  color:var(--accent);
  transform:translateX(2px);
}

.footer-meta{
  display:grid;
  grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);
  gap:clamp(24px,5vw,72px);
  padding-block:clamp(28px,4vw,44px);
  border-bottom:1px solid var(--rule-soft);
}
.footer-meta__title{
  padding-bottom:8px;
  margin-bottom:12px;
  border-bottom:1px solid var(--rule-soft);
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:700;
  letter-spacing:.16em;
  color:var(--gray);
  text-transform:uppercase;
}
.footer-meta__line{
  font-size:.9375rem;
  line-height:1.9;
  color:var(--text);
  max-width:46ch;
}
.footer-meta__line.mono{font-size:.875rem;}
.footer-meta__muted{
  color:var(--gray);
  font-size:.875rem;
}
.footer-legal{
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  gap:10px;
}
.footer-legal__links{
  display:flex;
  flex-wrap:wrap;
  gap:8px 20px;
}
.footer-legal__links a{
  position:relative;
  font-size:.875rem;
  color:var(--gray);
  text-decoration:none;
  transition:color .18s ease;
}
.footer-legal__links a::after{
  content:"";
  position:absolute;
  left:0;
  bottom:-2px;
  width:0;
  height:1px;
  background:var(--accent);
  transition:width .18s ease;
}
.footer-legal__links a:hover{color:var(--text);}
.footer-legal__links a:hover::after{width:100%;}
.footer-icp,
.footer-copy{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.04em;
  color:var(--gray);
}
.footer-track{
  position:relative;
  height:10px;
  background-image:repeating-linear-gradient(90deg,rgba(232,237,245,.16) 0 1px,transparent 1px 14px);
}
.footer-track::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  top:4px;
  height:1px;
  background:linear-gradient(90deg,var(--cyan),var(--magenta) 52%,var(--amber));
  opacity:.6;
}

/* ---------- 08 响应式 ---------- */
@media (max-width:1180px){
  .site-nav__idx{display:none;}
  .site-nav__list a{padding:13px 8px;}
}
@media (max-width:1080px){
  .header-util{display:none;}
  .face-switch{margin-left:auto;}
}
@media (max-width:960px){
  html{scroll-padding-top:96px;}
  .toc{position:static;top:auto;}

  .nav-toggle{display:inline-flex;position:relative;z-index:3;}
  .header-deck{border-top:0;background:none;}
  .header-deck__inner{min-height:0;}

  .site-nav{
    position:fixed;
    top:0;
    right:0;
    bottom:0;
    z-index:1;
    flex:0 0 auto;
    width:min(88vw,352px);
    flex-direction:column;
    align-items:stretch;
    gap:0;
    margin:0;
    padding:86px 0 28px;
    background:var(--panel);
    border-left:1px solid var(--rule-strong);
    box-shadow:-28px 0 60px rgba(0,0,0,.55);
    overflow-y:auto;
    transform:translateX(102%);
    visibility:hidden;
    transition:transform .22s ease,visibility 0s linear .22s;
  }
  .site-nav[data-open]{
    transform:translateX(0);
    visibility:visible;
    transition:transform .22s ease,visibility 0s linear 0s;
  }
  .site-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    flex-wrap:nowrap;
  }
  .site-nav__list a{
    display:flex;
    justify-content:flex-start;
    padding:15px 24px;
    border-bottom:1px solid var(--rule-soft);
    border-left:2px solid transparent;
    font-size:1rem;
    color:var(--text);
  }
  .site-nav__list a:hover{
    background:rgba(232,237,245,.05);
    border-bottom-color:var(--rule-soft);
  }
  .site-nav__list a[aria-current="page"]{
    border-bottom-color:var(--rule-soft);
    border-left-color:var(--accent);
    background:rgba(232,237,245,.06);
  }
  .site-nav__idx{display:inline;font-size:11px;}
  .site-nav__cta{
    margin:22px 24px 0;
    min-height:46px;
    width:calc(100% - 48px);
    justify-content:center;
  }

  .nav-scrim{
    display:block;
    position:fixed;
    inset:0;
    z-index:0;
    background:rgba(5,7,11,.66);
    opacity:0;
    visibility:hidden;
    pointer-events:none;
    transition:opacity .2s ease,visibility 0s linear .2s;
  }
  .nav-scrim[data-open]{
    opacity:1;
    visibility:visible;
    pointer-events:auto;
    transition:opacity .2s ease,visibility 0s linear 0s;
  }
  html[data-nav-locked]{overflow:hidden;}

  .footer-top,
  .footer-meta{grid-template-columns:1fr;}
}
@media (max-width:820px){
  .section-head{grid-template-columns:1fr;}
  .section-head__note{justify-self:start;text-align:left;}
  .grid--cards > *{grid-column:span 6;}
  .split-zone{grid-template-columns:1fr;}
  .split-zone::after{display:none;}
}
@media (max-width:640px){
  .grid--2,
  .grid--cards{grid-template-columns:1fr;}
  .grid--cards > *{grid-column:auto;}
  .ledger__row{grid-template-columns:1fr;gap:2px;}
  .footer-cols{gap:24px;}
}
@media (max-width:600px){
  .brand__text{display:none;}
  .brand__mark{width:40px;height:40px;}
  .face-switch__btn{font-size:10px;padding:6px 8px;letter-spacing:.04em;}
  .header-rail__inner{min-height:64px;padding-block:9px;}
}
@media (max-width:420px){
  .footer-cols{grid-template-columns:1fr;}
  .nav-toggle__label{display:none;}
}

/* ---------- 09 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  html{scroll-behavior:auto;}
  .has-js [data-reveal],
  [data-reveal]{
    opacity:1;
    transform:none;
  }
  .card:hover,
  .card:focus-within,
  .btn:hover,
  .footer-col a:hover{transform:none;}
}