:root{
  --bg:#f6f9fd;
  --surface:#ffffff;
  --ink:#0d1b2a;
  --muted:#5a6b7d;
  --brand:#0a84ff;
  --brand-2:#22d3ee;
  --deep:#07203c;
  --border:#e3ebf5;
  --radius:16px;
  --max:1160px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  line-height:1.7;-webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration:none}
.container{max-width:var(--max);margin:0 auto;padding:0 20px}

/* header */
.site-header{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.88);backdrop-filter:blur(12px);border-bottom:1px solid var(--border)}
.header-inner{display:flex;align-items:center;gap:24px;height:68px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:19px;letter-spacing:.2px}
.brand img{width:36px;height:36px;border-radius:9px}
.nav{display:flex;gap:22px;flex:1;flex-wrap:wrap}
.nav-link{color:var(--muted);font-size:15px;font-weight:500;padding:6px 0;border-bottom:2px solid transparent}
.nav-link:hover,.nav-link.active{color:var(--brand);border-color:var(--brand)}
.header-actions{display:flex;align-items:center;gap:14px}
.lang{font-size:14px;color:var(--muted);border:1px solid var(--border);border-radius:999px;padding:5px 12px}
.lang:hover{color:var(--brand);border-color:var(--brand)}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;border-radius:999px;padding:10px 22px;font-size:15px;font-weight:600;transition:.18s ease}
.btn-primary{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;box-shadow:0 8px 20px rgba(10,132,255,.28)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 12px 26px rgba(10,132,255,.34)}
.btn-ghost{border:1px solid rgba(255,255,255,.45);color:#fff}
.btn-ghost:hover{background:rgba(255,255,255,.12)}
.btn-lg{padding:14px 30px;font-size:16px}
.btn-row{display:flex;gap:14px;flex-wrap:wrap;margin-top:26px}
.btn-row.center{justify-content:center;margin-top:8px}
.section.alt .btn-ghost{border-color:var(--border);color:var(--ink)}

/* hero */
.hero{background:radial-gradient(1000px 500px at 15% 0%,#0e3f78 0%,var(--deep) 55%,#04162b 100%);color:#fff;padding:78px 0 88px}
.hero-inner{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center}
.hero h1{font-size:clamp(30px,4.2vw,50px);line-height:1.22;margin:0 0 18px;font-weight:800;letter-spacing:-.4px}
.hero .lead{font-size:18px;color:#c6dcf4;margin:0;max-width:34em}
.hero-art img{border-radius:22px;box-shadow:0 26px 60px rgba(0,0,0,.4)}

/* sections */
.section{padding:74px 0}
.section.alt{background:var(--surface)}
.section h2{font-size:clamp(24px,2.8vw,34px);margin:0 0 12px;text-align:center;font-weight:750}
.section .sub{text-align:center;color:var(--muted);margin:0 auto 40px;max-width:44em}
.grid{display:grid;gap:22px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:26px;transition:.2s ease}
.section.alt .card{background:var(--bg)}
.card:hover{transform:translateY(-3px);box-shadow:0 14px 34px rgba(13,27,42,.08);border-color:#cfe0f5}
.card h3{margin:0 0 8px;font-size:18px}
.card p{margin:0;color:var(--muted);font-size:15px}

/* prose */
.prose{max-width:820px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:44px}
.prose h1{font-size:32px;margin:0 0 8px}
.prose h2{font-size:20px;margin:30px 0 8px}
.prose p{color:var(--muted);margin:0 0 10px}

/* footer */
.site-footer{background:var(--deep);color:#c3d6ea;padding:56px 0 26px;margin-top:0}
.foot-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1fr;gap:34px}
.foot-brand img{width:40px;height:40px;border-radius:10px;margin-bottom:12px}
.foot-brand p{font-size:14px;color:#94b0cc;margin:0;max-width:32em}
.foot-col h3{color:#fff;font-size:15px;margin:0 0 12px}
.foot-col a{display:block;font-size:14px;color:#a9c3dc;padding:4px 0}
.foot-col a:hover{color:#fff}
.foot-bottom{border-top:1px solid rgba(255,255,255,.12);margin-top:34px;padding-top:18px;font-size:13px;color:#7e9ab6}

@media (max-width:900px){
  .hero-inner{grid-template-columns:1fr}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .foot-grid{grid-template-columns:1fr 1fr}
  .header-inner{height:auto;padding:12px 0;flex-wrap:wrap}
  .nav{order:3;width:100%;gap:16px}
}
@media (max-width:620px){
  .grid-3{grid-template-columns:1fr}
  .foot-grid{grid-template-columns:1fr}
  .prose{padding:26px}
}