:root{
  --brand-from:#4f46e5;
  --brand-to:#f43f5e;
  --bg-dark:#0b1020;
  --bg-card:#131a30;
  --line:rgba(255,255,255,.08);
  --text:#e2e8f0;
  --muted:#94a3b8;
}

html{scroll-behavior:smooth;}
body{
  font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg-dark);
  color:var(--text);
  -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(244,63,94,.10) 1px,transparent 1px),
    linear-gradient(90deg,rgba(79,70,229,.10) 1px,transparent 1px);
  background-size:44px 44px;
}
.nav-blur{
  background:rgba(11,16,32,.78);
  backdrop-filter:blur(18px);
  -webkit-backdrop-filter:blur(18px);
  border-bottom:1px solid var(--line);
  box-shadow:0 10px 40px rgba(0,0,0,.45);
}
.card-hover{
  background:var(--bg-card);
  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:rgba(244,63,94,.45);
  box-shadow:0 28px 60px -22px rgba(244,63,94,.35);
}
.btn-glow{
  background:linear-gradient(90deg,var(--brand-from),var(--brand-to));
  box-shadow:0 12px 32px -10px rgba(244,63,94,.6);
  transition:transform .25s ease,box-shadow .25s ease;
}
.btn-glow:hover{
  transform:translateY(-2px);
  box-shadow:0 18px 42px -12px rgba(244,63,94,.75);
}
.fade-in{opacity:0;transform:translateY(24px);transition:opacity .7s ease,transform .7s ease;}
.fade-in.visible{opacity:1;transform:translateY(0);}

/* FAQ */
.faq-item{
  background:var(--bg-card);
  border:1px solid var(--line);
  border-radius:16px;
  overflow:hidden;
  transition:border-color .3s ease,box-shadow .3s ease;
}
.faq-item.open{border-color:rgba(244,63,94,.5);box-shadow:0 18px 44px -20px rgba(244,63,94,.35);}
.faq-question{
  cursor:pointer;
  padding:20px 22px;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  font-weight:600;color:#f1f5f9;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:rgba(244,63,94,.15);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:#f8fafc;}
@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:3rem;line-height:1;font-weight:800;color:#fff;}
@media(min-width:768px){.stat-num{font-size:3.4rem;}}

/* 轮播 */
.carousel-track{display:flex;transition:transform .6s cubic-bezier(.4,0,.2,1);}
.slide{min-width:100%;}
.dot{width:10px;height:10px;border-radius:9999px;background:rgba(255,255,255,.25);cursor:pointer;transition:all .3s ease;}
.dot.active{background:linear-gradient(90deg,var(--brand-from),var(--brand-to));width:28px;}