:root{
  --bg:#0b0f17;
  --bg-soft:#121826;
  --card:#161e2e;
  --border:#222c40;
  --text:#e7ecf3;
  --muted:#9aa6b8;
  --accent:#5b8cff;
  --accent-2:#7c5cff;
  --max:980px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:radial-gradient(1200px 600px at 50% -10%,#16203a 0%,var(--bg) 55%);
  color:var(--text);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}

/* Header */
header.site{
  position:sticky;top:0;z-index:20;
  backdrop-filter:saturate(140%) blur(10px);
  background:rgba(11,15,23,.72);
  border-bottom:1px solid var(--border);
}
.nav{display:flex;align-items:center;justify-content:space-between;height:62px}
.brand{font-weight:700;font-size:18px;color:var(--text)}
.brand span{color:var(--accent)}
.menu{display:flex;gap:18px;align-items:center;flex-wrap:wrap}
.menu a{color:var(--muted);font-size:14px}
.menu a:hover{color:var(--text);text-decoration:none}
.langbtn{
  border:1px solid var(--border);background:var(--card);color:var(--text);
  padding:6px 12px;border-radius:999px;font-size:13px;cursor:pointer;
}
.langbtn:hover{border-color:var(--accent)}

/* Hero */
.hero{padding:84px 0 56px;text-align:center}
.hero h1{font-size:42px;line-height:1.15;margin:0 0 14px;letter-spacing:-.5px}
.hero h1 .grad{background:linear-gradient(90deg,var(--accent),var(--accent-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{font-size:18px;color:var(--muted);max-width:680px;margin:0 auto 28px}
.cta{display:inline-flex;gap:12px;flex-wrap:wrap;justify-content:center}
.btn{
  display:inline-block;padding:12px 22px;border-radius:10px;font-weight:600;font-size:15px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2));color:#fff;border:none;cursor:pointer;
}
.btn:hover{text-decoration:none;opacity:.92}
.btn.ghost{background:transparent;border:1px solid var(--border);color:var(--text)}

/* Sections */
section{padding:48px 0;border-top:1px solid var(--border)}
section h2{font-size:28px;margin:0 0 8px;letter-spacing:-.3px}
section .sub{color:var(--muted);margin:0 0 28px}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card{
  background:var(--card);border:1px solid var(--border);border-radius:14px;padding:22px;
}
.card h3{margin:0 0 8px;font-size:17px}
.card p{margin:0;color:var(--muted);font-size:14px}

/* Policy pages */
.doc{padding:48px 0 80px}
.doc h1{font-size:32px;margin:0 0 6px}
.doc .updated{color:var(--muted);font-size:13px;margin:0 0 28px}
.doc h2{font-size:20px;margin:34px 0 10px}
.doc p,.doc li{color:#cdd6e4;font-size:15px}
.doc ul{padding-left:20px}
.doc .box{background:var(--bg-soft);border:1px solid var(--border);border-radius:12px;padding:18px 20px;margin:20px 0}

/* Contact */
.kv{display:grid;grid-template-columns:160px 1fr;gap:8px 18px;margin:18px 0}
.kv dt{color:var(--muted);font-size:14px}
.kv dd{margin:0;font-size:15px}

/* Footer */
footer.site{border-top:1px solid var(--border);padding:30px 0;color:var(--muted);font-size:13px}
.foot{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}
.foot a{color:var(--muted);margin-right:16px}

/* Language toggle visibility */
[data-lang]{display:none}
html[lang="en"] [data-lang="en"]{display:revert}
html[lang="zh"] [data-lang="zh"]{display:revert}

@media (max-width:760px){
  .grid{grid-template-columns:1fr}
  .hero h1{font-size:32px}
  .kv{grid-template-columns:1fr}
  .menu{gap:12px}
}