/* ============ 设计变量 ============ */
:root{
  --bg:#0b0f1a;
  --bg-soft:#0f1525;
  --surface:#141b2e;
  --border:#223049;
  --text:#e8edf7;
  --muted:#9aa7bd;
  --primary:#4f46e5;
  --accent:#22d3ee;
  --radius:14px;
  --maxw:960px;
  --shadow:0 10px 30px rgba(0,0,0,.35);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%}
.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 20px}

/* ============ 按钮 ============ */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.4em;padding:12px 22px;border-radius:999px;font-weight:600;font-size:15px;cursor:pointer;border:1px solid transparent;transition:transform .15s ease,background .15s ease,opacity .15s ease}
.btn-sm{padding:9px 16px;font-size:14px}
.btn-block{width:100%}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff}
.btn-primary:hover{transform:translateY(-2px);opacity:.94}
.btn-ghost{background:transparent;border-color:var(--border);color:var(--text)}
.btn-ghost:hover{border-color:var(--accent);color:var(--accent)}
.btn-light{background:#fff;color:#0b0f1a}

/* ============ 顶部导航 ============ */
.site-header{position:sticky;top:0;z-index:50;backdrop-filter:saturate(140%) blur(10px);background:rgba(11,15,26,.72);border-bottom:1px solid var(--border)}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px}
.brand-mark{display:inline-flex}
.nav-links{display:flex;align-items:center;gap:26px;font-size:15px;color:var(--muted)}
.nav-links a:not(.btn):hover{color:var(--text)}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:0;cursor:pointer;padding:8px}
.nav-toggle span{width:24px;height:2px;background:var(--text);border-radius:2px;transition:.2s}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ============ Hero ============ */
.hero{padding:96px 0 72px;text-align:center}
.eyebrow{display:inline-block;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;letter-spacing:.15em;text-transform:uppercase;color:var(--accent);border:1px solid var(--border);padding:5px 12px;border-radius:999px;margin-bottom:22px}
.hero h1{font-size:clamp(30px,6vw,52px);line-height:1.2;font-weight:800;letter-spacing:-.01em}
.grad{background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;background-clip:text;color:transparent}
.lead{color:var(--muted);font-size:18px;max-width:620px;margin:20px auto 0}
.hero-actions{display:flex;gap:14px;justify-content:center;flex-wrap:wrap;margin-top:32px}

/* ============ 通用区块 ============ */
.section{padding:72px 0}
.section-soft{background:var(--bg-soft)}
.section-head{text-align:center;max-width:640px;margin:0 auto 44px}
.section-head h2{font-size:clamp(24px,4vw,34px);font-weight:750;margin-top:14px}
.section-sub{color:var(--muted);margin-top:12px;font-size:16px}

/* ============ 卡片网格 ============ */
.grid{display:grid;gap:22px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;transition:transform .15s ease,border-color .15s ease}
.card:hover{transform:translateY(-4px);border-color:var(--accent)}
.card-ic{width:48px;height:48px;display:flex;align-items:center;justify-content:center;border-radius:12px;background:rgba(79,70,229,.12);margin-bottom:16px}
.card h3{font-size:20px;margin-bottom:8px}
.card p{color:var(--muted);font-size:15px}

/* ============ 联系 ============ */
.contact-info{max-width:560px;margin:0 auto;text-align:center}
.contact-list{list-style:none;display:flex;flex-direction:column;gap:14px;margin:24px 0 28px;align-items:center}
.contact-list li{display:flex;align-items:center;gap:10px;color:var(--text);font-size:16px}
.contact-list svg{flex:none}

/* ============ 页脚 ============ */
.site-footer{border-top:1px solid var(--border);padding:26px 0;background:var(--bg-soft)}
.footer-bottom{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;color:var(--muted);font-size:13px}

/* ============ 响应式 ============ */
@media (max-width:768px){
  .nav-toggle{display:flex}
  .nav-links{position:absolute;top:64px;left:0;right:0;flex-direction:column;gap:0;background:var(--bg);border-bottom:1px solid var(--border);padding:8px 20px 18px;max-height:0;overflow:hidden;transition:max-height .25s ease}
  .nav-links.open{max-height:340px}
  .nav-links a{padding:12px 0;width:100%;border-bottom:1px solid var(--border)}
  .nav-links .nav-cta{margin-top:10px;border-bottom:0}
  .grid-2{grid-template-columns:1fr}
  .hero{padding:68px 0 48px}
}

/* ============ 无障碍 ============ */
@media (prefers-reduced-motion:reduce){
  *{scroll-behavior:auto !important;transition:none !important}
}