:root {
  --brand: #1677ff;
  --brand-d: #0958d9;
  --ok: #07c160;
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1f2329;
  --muted: #8a9099;
  --line: #eceef1;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
}
.app { max-width: 480px; margin: 0 auto; min-height: 100vh; padding-bottom: 30px; }
.topbar {
  position: sticky; top: 0; z-index: 10;
  background: var(--brand); color: #fff;
  text-align: center; font-size: 17px; font-weight: 600;
  padding: 14px 12px; box-shadow: 0 1px 4px rgba(0,0,0,.08);
}
.card {
  background: var(--card); border-radius: 12px;
  margin: 12px; padding: 16px; box-shadow: 0 1px 3px rgba(0,0,0,.04);
}
.list { padding: 4px 0; }
.item {
  display: flex; align-items: center; justify-content: space-between;
  background: var(--card); margin: 10px 12px; padding: 14px 16px;
  border-radius: 12px; text-decoration: none; color: inherit;
  box-shadow: 0 1px 3px rgba(0,0,0,.04); transition: transform .06s;
}
.item:active { transform: scale(.99); }
.item-main { flex: 1; min-width: 0; }
.item-name { font-size: 16px; font-weight: 600; }
.item-desc { color: var(--muted); font-size: 13px; margin-top: 4px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.item-side { text-align: right; margin-left: 12px; }
.item-price { color: #fa5151; font-size: 17px; font-weight: 700; }
.item-stock { color: var(--muted); font-size: 12px; margin-top: 2px; }
.prod-name { margin: 0 0 6px; font-size: 18px; }
.prod-price { color: #fa5151; font-size: 22px; font-weight: 700; }
.prod-desc { color: var(--muted); font-size: 14px; line-height: 1.6; white-space: pre-wrap; }
.pay-box { text-align: center; }
.tip { color: var(--text); margin: 0 0 14px; }
.tip strong { color: var(--brand); }
.qrcode {
  width: 220px; height: 220px; margin: 0 auto 12px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--line); border-radius: 8px; padding: 6px; background: #fff;
}
.qrcode img, .qrcode canvas { display: block; }
.loading { color: var(--muted); font-size: 13px; }
.qr-raw { font-size: 12px; color: var(--muted); word-break: break-all; line-height: 1.5; }
.qr-raw code { color: var(--brand); }
.status { margin: 14px 0; font-size: 15px; font-weight: 600; }
.status.ok { color: var(--ok); }
.status.danger { color: #fa5151; }
.card-result {
  text-align: left; background: #f7fbf8; border: 1px solid #cdeccd;
  border-radius: 10px; padding: 14px; margin-top: 6px;
}
.card-result .line { display: flex; justify-content: space-between; gap: 10px; padding: 6px 0; }
.card-result .line span { color: var(--muted); }
.card-result .line b { word-break: break-all; text-align: right; }
.card-result .warn { color: #b8870a; font-size: 13px; margin: 8px 0 0; }
.btn {
  display: inline-block; background: var(--brand); color: #fff;
  text-decoration: none; padding: 12px 28px; border-radius: 24px; font-weight: 600;
  margin-top: 10px;
}
.btn:active { background: var(--brand-d); }
.btn-ghost { display: inline-block; color: var(--brand); text-decoration: none; margin-top: 12px; font-size: 14px; }
.foot { text-align: center; color: var(--muted); font-size: 12px; margin-top: 24px; }

/* ===== 后台样式 ===== */
.admin { max-width: 960px; margin: 0 auto; padding: 16px; }
.admin .nav a { margin-right: 14px; color: var(--brand); text-decoration: none; font-size: 14px; }
.admin table { width: 100%; border-collapse: collapse; background: #fff; font-size: 14px; }
.admin th, .admin td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
.admin th { background: #fafbfc; }
.admin input, .admin textarea, .admin select {
  width: 100%; padding: 8px 10px; border: 1px solid var(--line); border-radius: 6px; font-size: 14px;
}
.admin textarea { min-height: 140px; font-family: monospace; }
.tag-ok { color: var(--ok); }
.tag-no { color: #fa5151; }
.login-box { max-width: 340px; margin: 80px auto; background: #fff; padding: 24px; border-radius: 12px; box-shadow: 0 2px 8px rgba(0,0,0,.06); }
.login-box h2 { text-align: center; margin: 0 0 18px; }
.login-box .row { margin-bottom: 12px; }
.login-box button { width: 100%; background: var(--brand); color: #fff; border: 0; padding: 11px; border-radius: 8px; font-size: 15px; font-weight: 600; }
.err { color: #fa5151; font-size: 13px; margin-bottom: 10px; }
.ok-msg { color: var(--ok); font-size: 13px; margin-bottom: 10px; }
.stat-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.stat { background: #fff; border-radius: 10px; padding: 16px; text-align: center; box-shadow: 0 1px 3px rgba(0,0,0,.04); }
.stat .num { font-size: 22px; font-weight: 700; color: var(--brand); }
.stat .lbl { color: var(--muted); font-size: 13px; margin-top: 4px; }
@media (max-width: 600px){ .stat-grid { grid-template-columns: repeat(2,1fr);} }