/* 基础样式与主题 */
:root{
  --bg:#0b1220;
  --card:#111a2b;
  --text:#e9f0ff;
  --muted:#9fb2d9;
  --primary:#0a66ff;
  --primary-600:#0b5ae0;
  --secondary:#1cc8a0;
  --accent:#ffd166;
  --border:#23314f;
  --container:1120px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,Helvetica,Arial,"PingFang SC","Microsoft YaHei",sans-serif}
a{color:var(--text);text-decoration:none}
img{max-width:100%;display:block}

.container{max-width:var(--container);margin:0 auto;padding:0 20px}

/* Header */
.site-header{position:sticky;top:0;z-index:20;background:rgba(11,18,32,.7);backdrop-filter:saturate(160%) blur(8px);border-bottom:1px solid var(--border)}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{font-weight:800;letter-spacing:.5px}
.nav a{margin-left:16px;color:var(--muted)}
.nav .btn{margin-left:12px}

/* Buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--border);border-radius:10px;padding:10px 16px;transition:.2s;background:transparent}
.btn:hover{transform:translateY(-1px)}
.btn-ghost{color:var(--text)}
.btn-primary{background:var(--primary);border-color:transparent;color:#fff}
.btn-primary:hover{background:var(--primary-600)}
.btn-secondary{background:var(--secondary);border-color:transparent;color:#07261d}
.btn-lg{padding:14px 22px;border-radius:12px;font-weight:700}

/* Hero */
.hero{background:radial-gradient(1200px 600px at 50% -10%, #163169 0%, transparent 60%), linear-gradient(180deg, #0b1220 0%, #0b1220 100%);padding:72px 0 48px;border-bottom:1px solid var(--border)}
.hero-inner{display:flex;flex-direction:column;gap:18px;align-items:flex-start}
.hero h1{margin:0;font-size:32px;line-height:1.28}
.subtitle{color:var(--muted);max-width:820px}
.cta-group{display:flex;gap:12px;margin-top:8px}
.trust-points{display:flex;gap:18px;list-style:none;padding:0;margin:12px 0 0;color:var(--muted);flex-wrap:wrap}

/* Sections */
.section{padding:56px 0;border-bottom:1px solid var(--border)}
.section.alt{background:linear-gradient(180deg, rgba(255,255,255,.02), rgba(255,255,255,0));}
.section h2{margin:0 0 16px 0}

.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:18px}
.bullet{color:var(--muted)}
.steps{counter-reset:stp;list-style:none;padding:0;margin:0}
.steps li{position:relative;padding-left:36px;margin:12px 0}
.steps li:before{counter-increment:stp;content:counter(stp);position:absolute;left:0;top:0;width:26px;height:26px;border-radius:6px;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700}
.note{margin-top:16px;padding:12px 14px;border-radius:10px;background:#0e1a30;border:1px dashed var(--border);color:var(--muted)}

/* Footer */
.site-footer{padding:32px 0}
.footer-inner{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.footer-nav a{margin-right:12px;color:var(--muted)}

/* Mobile CTA fixed bar */
.mobile-fixed-cta{position:fixed;left:0;right:0;bottom:0;z-index:30;display:none;background:rgba(11,18,32,.85);backdrop-filter:saturate(160%) blur(8px);border-top:1px solid var(--border)}
.mobile-fixed-cta .mobile-btn{flex:1;display:inline-flex;align-items:center;justify-content:center;padding:14px 8px;font-weight:700}
.mobile-btn.register{background:var(--primary);color:#fff}
.mobile-btn.download{background:var(--secondary);color:#07261d}

/* Utilities */
.hidden{display:none !important}

/* Responsive */
@media (max-width: 960px){
  .grid-3{grid-template-columns:1fr}
  .hero h1{font-size:26px}
}
@media (max-width: 720px){
  .nav a{display:none}
  .nav .btn{display:none}
  .mobile-fixed-cta{display:flex}
}