:root{
  --brand-from:#2563eb;
  --brand-to:#ef4444;
  --ink:#0f172a;
  --muted:#64748b;
  --line:#e2e8f0;
}

html{scroll-behavior:smooth;}
body{
  font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;
  background:#f8fafc;
  color:var(--ink);
  -webkit-font-smoothing:antialiased;
}

/* ---- 必需类名 ---- */
.gradient-text{
  background:linear-gradient(90deg,var(--brand-from),var(--brand-to));
  -webkit-background-clip:text;
  background-clip:text;
  color:transparent;
}
.bg-grid{
  background-image:linear-gradient(rgba(239,68,68,.07) 1px,transparent 1px),
    linear-gradient(90deg,rgba(37,99,235,.07) 1px,transparent 1px);
  background-size:46px 46px;
}
.nav-blur{
  background:rgba(255,255,255,.85);
  backdrop-filter:blur(16px);
  -webkit-backdrop-filter:blur(16px);
  box-shadow:0 8px 30px rgba(15,23,42,.08);
}
.card-hover{
  background:#fff;
  border:1px solid var(--line);
  transition:transform .35s ease,border-color .35s ease,box-shadow .35s ease;
}
.card-hover:hover{
  transform:translateY(-8px);
  border-color:var(--brand-to);
  box-shadow:0 24px 48px -18px rgba(239,68,68,.28);
}
.btn-glow{
  background:linear-gradient(90deg,var(--brand-from),var(--brand-to));
  box-shadow:0 12px 30px -10px rgba(239,68,68,.6);
  transition:transform .25s ease,box-shadow .25s ease;
}
.btn-glow:hover{
  transform:translateY(-2px);
  box-shadow:0 18px 40px -12px rgba(239,68,68,.75);
}
.fade-in{opacity:0;transform:translateY(22px);transition:opacity .7s ease,transform .7s ease;}
.fade-in.visible{opacity:1;transform:translateY(0);}

/* FAQ */
.faq-item{
  background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden;
  transition:border-color .3s ease,box-shadow .3s ease;
}
.faq-item.open{border-color:var(--brand-to);box-shadow:0 16px 40px -20px rgba(239,68,68,.3);}
.faq-question{
  cursor:pointer;padding:20px 22px;display:flex;align-items:center;justify-content:space-between;gap:16px;
  font-weight:600;color:var(--ink);text-align:left;
}
.faq-answer{max-height:0;overflow:hidden;transition:max-height .4s ease;padding:0 22px;color:var(--muted);line-height:1.8;}
.faq-item.open .faq-answer{max-height:320px;padding-bottom:22px;}
.faq-icon{
  flex:0 0 auto;width:28px;height:28px;border-radius:9999px;
  display:flex;align-items:center;justify-content:center;
  background:#fee2e2;color:var(--brand-to);transition:transform .35s ease;
}
.faq-item.open .faq-icon{transform:rotate(180deg);background:linear-gradient(90deg,var(--brand-from),var(--brand-to));color:#fff;}

/* ---- 主题辅助 ---- */
.section-title{font-size:2.1rem;font-weight:800;color:var(--ink);}
@media(min-width:640px){.section-title{font-size:2.5rem;}}
.eyebrow{font-size:.8rem;font-weight:700;letter-spacing:.18em;text-transform:uppercase;color:var(--brand-to);}
.stat-num{font-size:2.9rem;line-height:1;font-weight:800;color:var(--ink);}
@media(min-width:768px){.stat-num{font-size:3.2rem;}}

/* 内页页头 */
.page-hero{
  background:linear-gradient(135deg,#eff6ff 0%,#fff 45%,#fef2f2 100%);
}