:root {
  --bg: #f4f6f9;
  --card: #fff;
  --ink: #1a1f2e;
  --muted: #6b7289;
  --line: rgba(45, 53, 72, 0.1);
  --primary: #0d9f6e;
}

* { box-sizing: border-box; }
body.admin-body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
}
.admin-top {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem 1.25rem;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.admin-brand { font-weight: 700; }
.admin-nav { display: flex; gap: 0.75rem; flex: 1; }
.admin-nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 0.35rem 0.6rem;
  border-radius: 8px;
}
.admin-nav a.is-active,
.admin-nav a:hover {
  color: var(--primary);
  background: rgba(13, 159, 110, 0.08);
}
.admin-main { max-width: 1100px; margin: 0 auto; padding: 1.25rem; }
.page-title { margin: 0 0 0.5rem; }
.muted { color: var(--muted); }
.panel, .login-card, .stat-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1rem;
  margin-bottom: 1rem;
}
.login-card { max-width: 420px; margin: 4rem auto; }
.form-grid {
  display: grid;
  gap: 0.75rem;
}
.form-grid--wide {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.form-grid label { display: grid; gap: 0.35rem; font-size: 0.875rem; }
.form-grid .span-2 { grid-column: span 2; }
.form-grid input, .code-result textarea {
  width: 100%;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  font: inherit;
}
.btn {
  border: 0;
  border-radius: 8px;
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  font: inherit;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-ghost { background: transparent; color: var(--muted); }
.btn-sm { padding: 0.25rem 0.5rem; font-size: 0.8125rem; }
.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.75rem;
  margin: 1rem 0;
}
.settings-section-title {
  margin: 0.5rem 0 0;
  font-size: 1rem;
}
.settings-section-title:not(:first-child) {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}
.qr-preview {
  display: grid;
  gap: 0.5rem;
  justify-items: start;
}
.qr-preview img {
  width: 180px;
  height: 180px;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fafbfc;
}
.stat-card span { display: block; color: var(--muted); font-size: 0.8125rem; }
.stat-card strong { font-size: 1.5rem; }
.data-table { width: 100%; border-collapse: collapse; font-size: 0.875rem; }
.data-table th, .data-table td {
  border-bottom: 1px solid var(--line);
  padding: 0.55rem 0.35rem;
  text-align: left;
}
.flash { padding: 0.65rem 0.8rem; border-radius: 8px; margin-bottom: 0.75rem; }
.flash--ok { background: rgba(13, 159, 110, 0.12); color: #047857; }
.flash--error { background: rgba(239, 68, 68, 0.1); color: #b91c1c; }
.code-result textarea { margin-top: 0.5rem; font-family: Consolas, monospace; }
@media (max-width: 800px) {
  .stat-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .form-grid--wide { grid-template-columns: 1fr; }
  .form-grid .span-2 { grid-column: span 1; }
}