:root {
  --bg: #f5f6fa;
  --text: #1f2430;
  --nav-bg: #1f2430;
  --nav-text: #e5e7eb;
  --card-bg: #ffffff;
  --border: #e5e7eb;
  --table-head: #f0f1f5;
  --accent: #4f46e5;
  --muted: #6b7280;
}
[data-theme="dark"] {
  --bg: #12141c;
  --text: #e5e7eb;
  --nav-bg: #0b0d12;
  --nav-text: #e5e7eb;
  --card-bg: #1b1f2a;
  --border: #2a2f3d;
  --table-head: #232838;
  --accent: #818cf8;
  --muted: #9ca3af;
}

* { box-sizing: border-box; font-family: -apple-system, Segoe UI, Roboto, Arial, sans-serif; }
body { margin: 0; background: var(--bg); color: var(--text); }
.topnav { display: flex; gap: 14px; background: var(--nav-bg); padding: 12px 24px; flex-wrap: wrap; align-items: center; }
.topnav a { color: var(--nav-text); text-decoration: none; font-size: 13px; }
.topnav a.logout { margin-left: auto; color: #f87171; }
.theme-toggle { background: transparent; border: 1px solid var(--nav-text); color: var(--nav-text); border-radius: 4px; padding: 4px 8px; font-size: 12px; cursor: pointer; }
.container { max-width: 1100px; margin: 24px auto; padding: 0 16px; }
h1 { margin-top: 0; }
.card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 8px; padding: 20px; margin-bottom: 20px; display: flex; flex-direction: column; gap: 12px; max-width: 480px; }
.card label { display: flex; flex-direction: column; font-size: 13px; gap: 4px; }
.card input, .card select, .card textarea { padding: 8px; border: 1px solid var(--border); border-radius: 4px; font-size: 14px; background: var(--card-bg); color: var(--text); }
.card button { padding: 10px; border: none; border-radius: 4px; background: var(--accent); color: #fff; cursor: pointer; font-size: 14px; }
.data-table { width: 100%; border-collapse: collapse; background: var(--card-bg); border-radius: 8px; overflow: hidden; margin-bottom: 24px; }
.data-table th, .data-table td { padding: 10px 12px; border-bottom: 1px solid var(--border); text-align: left; font-size: 13px; }
.data-table th { background: var(--table-head); }
.stat-grid { display: flex; gap: 16px; margin-bottom: 24px; flex-wrap: wrap; }
.stat-card { background: var(--card-bg); border-radius: 8px; padding: 20px; min-width: 140px; display: flex; flex-direction: column; gap: 4px; }
.stat-num { font-size: 28px; font-weight: 700; color: var(--accent); }
.login-box { max-width: 360px; margin: 80px auto; background: var(--card-bg); padding: 32px; border-radius: 8px; color: var(--text); }
.login-box form { display: flex; flex-direction: column; gap: 12px; }
.login-box input { padding: 10px; border: 1px solid var(--border); border-radius: 4px; }
.login-box button { padding: 10px; background: var(--accent); color: #fff; border: none; border-radius: 4px; cursor: pointer; }
.error { color: #dc2626; }
.success { color: #16a34a; }
.inline-form { display: flex; gap: 4px; align-items: center; }
.heatmap { display: grid; grid-template-columns: repeat(10, 1fr); gap: 4px; max-width: 400px; margin-bottom: 24px; }
.heat-cell { width: 32px; height: 32px; border-radius: 4px; }