:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #dc2626;
  --success: #16a34a;
  --warning: #d97706;
  --bg: #f8fafc;
  --card: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --text-muted: #64748b;
  --header-bg: #1e293b;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

header {
  background: var(--header-bg);
  color: #fff;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 10;
}

header .logo { font-weight: 700; font-size: 16px; letter-spacing: 0.5px; }
header .user-info { font-size: 14px; display: flex; align-items: center; gap: 16px; }
header .btn-logout {
  background: transparent; border: 1px solid #475569;
  color: #cbd5e1; padding: 4px 12px; border-radius: 4px;
  cursor: pointer; font-size: 13px;
}
header .btn-logout:hover { border-color: #94a3b8; color: #fff; }

nav {
  background: #f1f5f9;
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  display: flex;
  gap: 4px;
}
nav a {
  display: inline-block;
  padding: 10px 16px;
  text-decoration: none;
  color: var(--text-muted);
  font-size: 14px;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}
nav a:hover { color: var(--primary); }
nav a.active { color: var(--primary); border-bottom-color: var(--primary); font-weight: 500; }

main { padding: 24px; max-width: 1200px; margin: 0 auto; }

.page-title {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--text);
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: background 0.15s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #b91c1c; }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #15803d; }
.btn-secondary { background: #f1f5f9; color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: #e2e8f0; }
.btn-sm { padding: 4px 10px; font-size: 12px; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
th, td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}
th {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  background: #f8fafc;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: #f8fafc; }

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.3px;
}
.badge-active, .badge-confirmed { background: #dcfce7; color: #15803d; }
.badge-inactive, .badge-rejected { background: #fee2e2; color: #b91c1c; }
.badge-pending, .badge-open { background: #fef9c3; color: #92400e; }
.badge-closed, .badge-approved { background: #e0f2fe; color: #0369a1; }
.badge-submitted { background: #f3e8ff; color: #7e22ce; }
.badge-paid { background: #dcfce7; color: #15803d; }
.badge-overdue { background: #fee2e2; color: #b91c1c; }

.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 100;
  align-items: center;
  justify-content: center;
}
.modal-overlay.open { display: flex; }

.modal {
  background: #fff;
  border-radius: 10px;
  padding: 24px;
  width: 480px;
  max-width: 95vw;
  max-height: 90vh;
  overflow-y: auto;
}
.modal-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 20px;
}
.modal-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
  margin-top: 20px;
}

.form-group { margin-bottom: 14px; }
.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 4px;
  color: var(--text-muted);
}
.form-group input, .form-group select, .form-group textarea {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  color: var(--text);
}
.form-group input:focus, .form-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(37,99,235,0.15);
}

.alert {
  padding: 12px 16px;
  border-radius: 6px;
  font-size: 14px;
  margin-bottom: 16px;
}
.alert-error { background: #fee2e2; color: #991b1b; }
.alert-success { background: #dcfce7; color: #14532d; }
.alert-info { background: #e0f2fe; color: #075985; }

.loading { text-align: center; padding: 40px; color: var(--text-muted); }
.empty { text-align: center; padding: 40px; color: var(--text-muted); font-size: 14px; }

input[type="number"] { -moz-appearance: textfield; }
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button { -webkit-appearance: none; }