:root{
  --brand-from:#4f46e5;
  --brand-to:#0ea5e9;
  --ink:#0b1220;
  --muted:#5b6474;
}
html{scroll-behavior:smooth;}
body{
  font-family:system-ui,-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:#f4f8fd;
  color:var(--ink);
  margin:0;
}
/* 渐变文字 */
.gradient-text{
  background:linear-gradient(120deg,var(--brand-from),var(--brand-to));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
/* 网格背景 */
.bg-grid{
  background-image:linear-gradient(rgba(79,70,229,.05) 1px,transparent 1px),
    linear-gradient(90deg,rgba(79,70,229,.05) 1px,transparent 1px);
  background-size:42px 42px;
}
/* 毛玻璃导航 */
.nav-blur{
  background:rgba(255,255,255,.84);
  backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);
  box-shadow:0 6px 30px rgba(11,18,32,.08);
}
/* 卡片 hover */
.card-hover{transition:transform .35s ease,box-shadow .35s ease,border-color .35s ease;}
.card-hover:hover{
  transform:translateY(-10px);
  box-shadow:0 26px 50px -18px rgba(14,165,233,.35);
  border-color:rgba(14,165,233,.55)!important;
}
/* 按钮发光 */
.btn-glow{box-shadow:0 10px 30px -8px rgba(14,165,233,.5);transition:transform .3s ease,box-shadow .3s ease;}
.btn-glow:hover{transform:translateY(-3px);box-shadow:0 18px 42px -8px rgba(14,165,233,.7);}
/* 入场动画 */
.fade-in{animation:fadeInUp 1s ease both;}
@keyframes fadeInUp{from{opacity:0;transform:translateY(30px);}to{opacity:1;transform:translateY(0);}}
/* FAQ 手风琴 */
.faq-item{border:1px solid #ddeaf7;border-radius:14px;background:#fff;overflow:hidden;margin-bottom:12px;transition:box-shadow .3s ease;}
.faq-item.open{box-shadow:0 16px 36px -22px rgba(14,165,233,.4);border-color:#bae6fd;}
.faq-question{cursor:pointer;display:flex;justify-content:space-between;align-items:center;padding:18px 22px;font-weight:600;color:#0b1220;}
.faq-answer{max-height:0;overflow:hidden;transition:max-height .4s ease,padding .4s ease;color:#5b6474;line-height:1.8;}
.faq-item.open .faq-answer{max-height:220px;padding:0 22px 18px;}
.faq-icon{transition:transform .35s ease;color:var(--brand-to);}
.faq-item.open .faq-icon{transform:rotate(180deg);}
/* 安卓徽章 */
.android-badge{
  background:linear-gradient(135deg,#22c55e,#16a34a);
  box-shadow:0 12px 30px -8px rgba(34,197,94,.55);
  animation:floaty 4s ease-in-out infinite;
}
@keyframes floaty{0%,100%{transform:translateY(0);}50%{transform:translateY(-12px);}}
/* 滚动渐入 */
.reveal{opacity:0;transform:translateY(26px);transition:all .7s ease;}
.reveal.visible{opacity:1;transform:translateY(0);}
/* 子页标题区 */
.page-hero{background:linear-gradient(135deg,#4f46e5 0%,#0ea5e9 100%);}
/* 版本卡片 */
.ver-card{border:1px solid #e2edf8;border-radius:18px;background:#fff;transition:transform .35s ease,box-shadow .35s ease;}
.ver-card:hover{transform:translateY(-8px);box-shadow:0 24px 48px -18px rgba(79,70,229,.3);}