:root {
  --bg: #0f1419;
  --surface: #1a2028;
  --surface-2: #232b36;
  --border: #2d3748;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --primary: #2ea043;
  --primary-hover: #3fb950;
  --danger: #f85149;
  --warning: #d29922;
  --accent: #58a6ff;
  --radius: 10px;
  --shadow: 0 4px 12px rgba(0,0,0,.25);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

.navbar {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
  margin-bottom: 28px;
}
.nav-inner { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.brand { font-size: 18px; font-weight: 700; color: var(--text); text-decoration: none; }
.nav-links { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.nav-links a { color: var(--text-muted); text-decoration: none; font-size: 14px; font-weight: 500; }
.nav-links a:hover { color: var(--text); }
.user { color: var(--text-muted); font-size: 14px; }

h1 { font-size: 26px; margin: 0 0 6px; }
h2 { font-size: 20px; margin: 0 0 16px; }
.muted { color: var(--text-muted); font-size: 14px; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin: 24px 0; }
.stat { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; }
.stat-label { color: var(--text-muted); font-size: 13px; text-transform: uppercase; letter-spacing: .5px; }
.stat-value { font-size: 26px; font-weight: 700; margin-top: 6px; }
.stat-value.green { color: var(--primary-hover); }
.stat-value.red { color: var(--danger); }
.stat-value.amber { color: var(--warning); }

.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; margin-bottom: 24px; box-shadow: var(--shadow); }
.card-header { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { padding: 12px 10px; text-align: left; border-bottom: 1px solid var(--border); }
th { color: var(--text-muted); font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: .5px; }
tbody tr:hover { background: var(--surface-2); }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

.badge { display: inline-block; padding: 3px 10px; border-radius: 999px; font-size: 12px; font-weight: 600; }
.badge-paid { background: rgba(46,160,67,.15); color: var(--primary-hover); }
.badge-unpaid { background: rgba(248,81,73,.15); color: var(--danger); }

.btn { display: inline-block; background: var(--primary); color: #fff; border: 0; padding: 9px 16px; border-radius: 6px; font-size: 14px; font-weight: 600; cursor: pointer; text-decoration: none; }
.btn:hover { background: var(--primary-hover); }
.btn-secondary { background: var(--surface-2); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: var(--border); }
.btn-danger { background: var(--danger); }
.btn-sm { padding: 5px 10px; font-size: 12px; }
.btn-link { color: var(--accent); text-decoration: none; font-size: 14px; }

.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; }
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 13px; color: var(--text-muted); font-weight: 500; }
.field input, .field select, .field textarea { background: var(--bg); color: var(--text); border: 1px solid var(--border); border-radius: 6px; padding: 9px 11px; font-size: 14px; font-family: inherit; }
.field input:focus, .field select:focus, .field textarea:focus { outline: none; border-color: var(--accent); }
.field textarea { min-height: 80px; resize: vertical; }
.form-actions { display: flex; gap: 10px; margin-top: 18px; }

.flash { padding: 12px 16px; border-radius: 8px; margin-bottom: 18px; font-size: 14px; }
.flash-success { background: rgba(46,160,67,.15); color: var(--primary-hover); border: 1px solid rgba(46,160,67,.3); }
.flash-error { background: rgba(248,81,73,.15); color: var(--danger); border: 1px solid rgba(248,81,73,.3); }

.login-wrap { max-width: 380px; margin: 80px auto; }
.login-wrap .card { padding: 28px; }

.footer { padding: 30px 0; color: var(--text-muted); text-align: center; }
.actions { display: flex; gap: 6px; flex-wrap: wrap; }

@media (max-width: 640px) {
  .stat-value { font-size: 22px; }
  h1 { font-size: 22px; }
}