:root {
  --primary: #0d9488;
  --primary-dark: #0f766e;
  --primary-light: #f0fdfa;
  --success: #16a34a;
  --warning: #d97706;
  --danger: #dc2626;
  --info: #0891b2;
  --dark: #0f172a;
  --light: #f8fafc;
  --muted: #64748b;
  --border: #e2e8f0;
  --sidebar-width: 256px;
}

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

body {
  font-family: system-ui, -apple-system, sans-serif;
  background: #f8fafc;
  color: var(--dark);
  min-height: 100vh;
}

/* ---- Cards ---- */
.card {
  background: #fff;
  border-radius: .5rem;
  border: 1px solid var(--border);
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: .75rem;
}

.card-title { font-size: .9rem; font-weight: 600; color: var(--dark); }

/* ---- Stat cards ---- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-card {
  background: #fff;
  border-radius: .5rem;
  border: 1px solid var(--border);
  padding: 1rem 1.25rem;
}

.stat-label { font-size: .7rem; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; font-weight: 500; }
.stat-value { font-size: 1.65rem; font-weight: 700; line-height: 1.2; margin-top: .2rem; color: var(--dark); }
.stat-sub { font-size: .75rem; color: var(--muted); margin-top: .2rem; }

.stat-card.danger  { border-left: 3px solid var(--danger); }
.stat-card.warning { border-left: 3px solid var(--warning); }
.stat-card.success { border-left: 3px solid var(--success); }
.stat-card.info    { border-left: 3px solid var(--primary); }

/* ---- Alerts ---- */
.alert {
  display: flex;
  align-items: flex-start;
  gap: .6rem;
  padding: .7rem 1rem;
  border-radius: .4rem;
  margin-bottom: .75rem;
  font-size: .875rem;
  border: 1px solid transparent;
}
.alert-danger  { background: #fef2f2; border-color: #fecaca; color: #991b1b; }
.alert-warning { background: #fffbeb; border-color: #fde68a; color: #92400e; }
.alert-success { background: #f0fdf4; border-color: #bbf7d0; color: #166534; }
.alert-info    { background: var(--primary-light); border-color: #99f6e4; color: #134e4a; }

/* ---- Tables ---- */
.table-wrap { overflow-x: auto; }

table { width: 100%; border-collapse: collapse; font-size: .875rem; }
thead th {
  background: #f8fafc;
  padding: .55rem .75rem;
  text-align: left;
  font-size: .7rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--muted);
  font-weight: 600;
  border-bottom: 1px solid var(--border);
}
tbody td {
  padding: .65rem .75rem;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
  color: #1e293b;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: #f8fafc; }

/* ---- Badges ---- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: .2rem .5rem;
  border-radius: 4px;
  font-size: .68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .04em;
  white-space: nowrap;
}
.badge-pending   { background: #fef9c3; color: #854d0e; }
.badge-approved  { background: #dcfce7; color: #166534; }
.badge-rejected  { background: #fee2e2; color: #991b1b; }
.badge-expired   { background: #fee2e2; color: #991b1b; }
.badge-critical  { background: #fee2e2; color: #991b1b; }
.badge-warning   { background: #fef9c3; color: #854d0e; }
.badge-ok        { background: #dcfce7; color: #166534; }
.badge-overpaid  { background: #dcfce7; color: #166534; }
.badge-underpaid { background: #fee2e2; color: #991b1b; }
.badge-settled   { background: #ccfbf1; color: #134e4a; }

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .4rem .85rem;
  border-radius: .35rem;
  border: none;
  cursor: pointer;
  font-size: .825rem;
  font-weight: 500;
  text-decoration: none;
  transition: opacity .15s, background .15s;
  white-space: nowrap;
}
.btn:hover { opacity: .85; }
.btn-primary   { background: var(--primary); color: #fff; }
.btn-success   { background: var(--success); color: #fff; }
.btn-danger    { background: var(--danger); color: #fff; }
.btn-warning   { background: var(--warning); color: #fff; }
.btn-secondary { background: #64748b; color: #fff; }
.btn-sm        { padding: .25rem .55rem; font-size: .775rem; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: #374151;
}
.btn-outline:hover { background: #f8fafc; opacity: 1; }

/* ---- Forms ---- */
.form-wrap { max-width: 640px; }

.form-group { margin-bottom: 1rem; }
.form-group label { display: block; font-size: .85rem; font-weight: 500; margin-bottom: .3rem; color: #374151; }
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: .45rem .75rem;
  border: 1px solid var(--border);
  border-radius: .35rem;
  font-size: .9rem;
  background: #fff;
  color: var(--dark);
  transition: border-color .15s, box-shadow .15s;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(13, 148, 136, .12);
}
.form-error  { color: var(--danger); font-size: .8rem; margin-top: .25rem; }
.form-actions { margin-top: 1.25rem; display: flex; gap: .5rem; align-items: center; }

/* ---- Page header ---- */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}
.page-header h2 { font-size: 1rem; font-weight: 700; color: var(--dark); }

/* ---- Misc ---- */
.text-muted   { color: var(--muted); }
.text-danger  { color: var(--danger); }
.text-success { color: var(--success); }
.text-warning { color: var(--warning); }
.d-flex  { display: flex; }
.gap-2   { gap: .5rem; }
.align-center { align-items: center; }
.flex-wrap { flex-wrap: wrap; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
@media (max-width: 768px) { .two-col { grid-template-columns: 1fr; } }

.overdue-row { background: #fef2f2 !important; }

/* ---- Mobile ---- */
@media (max-width: 1023px) {
  .form-actions {
    flex-direction: column;
    align-items: stretch;
  }
  .page-header {
    flex-direction: column;
    align-items: flex-start;
    gap: .5rem;
  }
  .table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}