/* 星辰数字服务 · 站点样式 */
*{margin:0;padding:0;box-sizing:border-box;-webkit-font-smoothing:antialiased}
:root{
  --brand:#2F6BFF; --brand-2:#5C8CFF; --bg:#F5F8FE; --surface:#fff;
  --text:#101828; --sub:#5B6B85; --line:#E3EAF5; --soft:#F0F5FD;
  --ok:#12B76A; --err:#F04438;
  --r-lg:22px; --r-md:16px; --r-sm:12px;
  --shadow:0 2px 10px rgba(24,52,110,.06), 0 0 0 1px rgba(24,52,110,.04);
}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",Roboto,sans-serif;
  background:var(--bg); color:var(--text); line-height:1.65; font-size:15px;
}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
a{color:inherit;text-decoration:none}

/* ---------- Header ---------- */
.hdr{background:rgba(255,255,255,.9);backdrop-filter:blur(16px);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
.hdr-in{display:flex;align-items:center;justify-content:space-between;height:70px}
.brand{display:flex;align-items:center;gap:12px}
.logo{
  width:40px;height:40px;border-radius:12px;display:grid;place-items:center;
  background:linear-gradient(135deg,var(--brand),var(--brand-2));
  color:#fff;font-weight:700;font-size:19px;box-shadow:0 6px 16px -6px rgba(47,107,255,.7)
}
.brand-txt{display:flex;flex-direction:column;line-height:1.25}
.brand-txt strong{font-size:16px;letter-spacing:.2px}
.brand-txt small{font-size:11.5px;color:var(--sub)}
.nav{display:flex;gap:26px;font-size:14px;color:var(--sub)}
.nav a:hover{color:var(--brand)}

/* ---------- Hero ---------- */
.hero{padding:56px 0 34px;text-align:center}
.hero h1{font-size:34px;font-weight:700;letter-spacing:-.5px;margin-bottom:12px}
.hero p{color:var(--sub);font-size:15.5px;max-width:620px;margin:0 auto}

/* ---------- Grid ---------- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(268px,1fr));gap:20px;padding:14px 0 48px}
.card{
  background:var(--surface);border-radius:var(--r-lg);padding:22px;
  box-shadow:var(--shadow);display:flex;flex-direction:column;
  transition:transform .18s ease, box-shadow .18s ease
}
.card:hover{transform:translateY(-3px);box-shadow:0 12px 28px -12px rgba(24,52,110,.22),0 0 0 1px rgba(24,52,110,.05)}
.card-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}
.tag{
  font-size:11.5px;font-weight:600;padding:4px 11px;border-radius:99px;
  background:#EAF1FF;color:var(--brand);letter-spacing:.3px
}
.stock{font-size:11.5px;color:var(--sub)}
.card h3{font-size:17px;font-weight:650;margin-bottom:8px;letter-spacing:.1px}
.desc{color:var(--sub);font-size:13.5px;line-height:1.7;flex:1}
.card-foot{display:flex;align-items:center;justify-content:space-between;margin-top:18px;padding-top:16px;border-top:1px solid var(--line)}
.price{font-size:20px;font-weight:700;color:var(--brand)}
.price-lg{font-size:30px;font-weight:700;color:var(--brand);letter-spacing:-.5px}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  height:40px;padding:0 20px;border-radius:11px;border:none;cursor:pointer;
  background:var(--brand);color:#fff;font-size:14px;font-weight:600;font-family:inherit;
  transition:background .16s, transform .12s;
}
.btn:hover{background:#2559DB}
.btn:active{transform:scale(.98)}
.btn-lg{height:50px;padding:0 30px;font-size:15.5px;border-radius:13px}
.btn-block{width:100%}

/* ---------- About ---------- */
.about{background:var(--surface);border-radius:var(--r-lg);padding:36px;box-shadow:var(--shadow);margin-bottom:56px}
.about h2{font-size:20px;margin-bottom:12px}
.about>p{color:var(--sub);font-size:14.5px;max-width:760px}
.feat{list-style:none;display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:16px;margin-top:26px}
.feat li{background:var(--soft);border-radius:var(--r-md);padding:16px 18px}
.feat b{display:block;font-size:14.5px;margin-bottom:4px}
.feat span{font-size:12.5px;color:var(--sub)}

/* ---------- Detail ---------- */
.back{display:inline-block;margin:28px 0 16px;color:var(--sub);font-size:13.5px}
.back:hover{color:var(--brand)}
.detail{background:var(--surface);border-radius:var(--r-lg);box-shadow:var(--shadow);overflow:hidden;margin-bottom:56px}
.detail-head{padding:34px;border-bottom:1px solid var(--line)}
.detail-head h1{font-size:26px;margin:14px 0 10px;letter-spacing:-.3px}
.price-row{display:flex;align-items:baseline;gap:16px;margin-top:20px}
.detail-body{padding:30px 34px}
.detail-body h2{font-size:16px;margin-bottom:14px}
.pre{
  font-family:inherit;white-space:pre-wrap;color:var(--sub);
  font-size:14px;line-height:1.9;background:var(--soft);
  border-radius:var(--r-md);padding:20px
}
.detail-foot{padding:0 34px 34px}

/* ---------- Buy ---------- */
.buy{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-bottom:56px}
.buy-sum,.buy-form{background:var(--surface);border-radius:var(--r-lg);box-shadow:var(--shadow);padding:30px}
.buy-sum h2{font-size:20px;margin-bottom:10px}
.sum-row{display:flex;justify-content:space-between;align-items:center;padding:13px 0;border-bottom:1px solid var(--line);font-size:14px}
.sum-row:last-child{border-bottom:none}
.sum-row span{color:var(--sub)}
.sum-row.total{padding-top:18px}
.buy-form label{display:block;margin-bottom:18px}
.buy-form label span{display:block;font-size:13px;color:var(--sub);margin-bottom:7px}
.buy-form label i{color:var(--err);font-style:normal}
.buy-form input,.buy-form textarea{
  width:100%;padding:12px 15px;border:1.5px solid var(--line);border-radius:var(--r-sm);
  font-family:inherit;font-size:14.5px;color:var(--text);background:#FBFDFF;
  transition:border-color .16s, box-shadow .16s, background .16s;
}
.buy-form input:focus,.buy-form textarea:focus{
  outline:none;border-color:var(--brand);background:#fff;
  box-shadow:0 0 0 3.5px rgba(47,107,255,.13)
}
.buy-form textarea{resize:vertical;min-height:82px}
.tip{font-size:12.5px;color:var(--sub);text-align:center;margin-top:14px}

/* ---------- Done ---------- */
.done{background:var(--surface);border-radius:var(--r-lg);box-shadow:var(--shadow);padding:48px 34px;text-align:center;margin:34px 0 56px}
.done-icon{
  width:62px;height:62px;border-radius:50%;margin:0 auto 20px;
  background:#E7F8EF;color:var(--ok);display:grid;place-items:center;font-size:30px;font-weight:700
}
.done h1{font-size:23px;margin-bottom:8px}
.done-sub{color:var(--sub);font-size:14px}
.done-box{max-width:420px;margin:26px auto;text-align:left;background:var(--soft);border-radius:var(--r-md);padding:8px 20px}
.done .btn{margin-top:8px}

/* ---------- Flash ---------- */
.flash{
  background:#E7F8EF;color:#08733F;border-radius:var(--r-sm);
  padding:13px 18px;font-size:13.5px;margin:24px 0
}
.flash-err{background:#FEECEB;color:#B42318}

.empty{color:var(--sub);text-align:center;padding:60px 0;grid-column:1/-1}

/* ---------- Footer ---------- */
.ftr{background:#0F1B33;color:#C3CFE6;padding:40px 0;margin-top:auto}
.ftr-in{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:26px;font-size:13px;line-height:1.9}
.ftr strong{color:#fff;font-size:14.5px}
.ftr p{color:#8497B8}
.ftr-icp{text-align:right}
@media(max-width:720px){
  .hdr-in{height:62px}
  .nav{display:none}
  .hero{padding:38px 0 24px}
  .hero h1{font-size:26px}
  .buy{grid-template-columns:1fr}
  .ftr-icp{text-align:left}
  .detail-head,.detail-body,.detail-foot{padding-left:22px;padding-right:22px}
}