:root {
  --color-bg: #f4f6f9;
  --color-surface: #ffffff;
  --color-border: #e2e5eb;
  --color-text: #1f2430;
  --color-text-muted: #6b7280;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-danger: #dc2626;
  --color-success: #16a34a;
  --color-warn: #d97706;
  --radius: 8px;
  --sidebar-w: 230px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--color-bg); color: var(--color-text); }

/* ---------- Auth page ---------- */
.auth-page { min-height: 100vh; display: flex; align-items: center; justify-content: center; }
.auth-card { background: var(--color-surface); padding: 40px; border-radius: var(--radius); width: 360px; box-shadow: 0 4px 24px rgba(0,0,0,.08); text-align: center; }
.auth-card h1 { margin: 0 0 4px; font-size: 22px; }
.auth-subtitle { color: var(--color-text-muted); margin-bottom: 24px; font-size: 14px; }
.auth-card form { text-align: left; }
.auth-card label { display: block; font-size: 13px; margin: 12px 0 4px; font-weight: 600; }
.auth-card input { width: 100%; padding: 10px 12px; border: 1px solid var(--color-border); border-radius: var(--radius); font-size: 14px; }

/* ---------- Buttons ---------- */
.btn { display: inline-block; padding: 9px 16px; border-radius: var(--radius); border: 1px solid transparent; font-size: 14px; font-weight: 600; cursor: pointer; text-decoration: none; }
.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-dark); }
.btn-secondary { background: #fff; color: var(--color-text); border-color: var(--color-border); }
.btn-danger { background: var(--color-danger); color: #fff; }
.btn-block { width: 100%; margin-top: 18px; }
.btn-link { background: none; border: none; color: var(--color-primary); cursor: pointer; font-size: 13px; }

/* ---------- Alerts ---------- */
.alert { padding: 10px 14px; border-radius: var(--radius); font-size: 13px; margin-bottom: 14px; }
.alert-error { background: #fef2f2; color: var(--color-danger); border: 1px solid #fecaca; }
.alert-success { background: #f0fdf4; color: var(--color-success); border: 1px solid #bbf7d0; }

/* ---------- Admin shell ---------- */
.admin-shell { display: flex; min-height: 100vh; }
.sidebar { width: var(--sidebar-w); background: #111827; color: #cbd5e1; flex-shrink: 0; }
.sidebar-brand { padding: 20px; font-weight: 700; color: #fff; font-size: 16px; border-bottom: 1px solid #1f2937; }
.sidebar-nav { display: flex; flex-direction: column; padding: 12px 0; }
.sidebar-nav a { color: #cbd5e1; padding: 10px 20px; text-decoration: none; font-size: 14px; }
.sidebar-nav a:hover { background: #1f2937; color: #fff; }

.main-col { flex: 1; display: flex; flex-direction: column; min-width: 0; }
.topbar { display: flex; justify-content: space-between; align-items: center; padding: 14px 24px; background: var(--color-surface); border-bottom: 1px solid var(--color-border); }
.topbar-title { font-weight: 700; font-size: 18px; }
.topbar-user { display: flex; gap: 14px; align-items: center; font-size: 13px; color: var(--color-text-muted); }
.content { padding: 24px; }

/* ---------- Stats ---------- */
.quick-actions { display: flex; gap: 10px; margin-bottom: 20px; flex-wrap: wrap; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 14px; margin-bottom: 28px; }
.stat-card { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); padding: 16px; }
.stat-card-warn { border-color: #fde68a; background: #fffbeb; }
.stat-label { font-size: 12px; color: var(--color-text-muted); margin-bottom: 6px; }
.stat-value { font-size: 22px; font-weight: 700; }

/* ---------- Tables ---------- */
.data-table { width: 100%; border-collapse: collapse; background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); overflow: hidden; }
.data-table th, .data-table td { padding: 10px 14px; text-align: left; font-size: 13px; border-bottom: 1px solid var(--color-border); }
.data-table th { background: #f9fafb; font-weight: 600; color: var(--color-text-muted); }
.empty-row { text-align: center; color: var(--color-text-muted); padding: 24px; }

.badge { padding: 3px 9px; border-radius: 999px; font-size: 11px; font-weight: 600; text-transform: capitalize; }
.badge-draft { background: #e5e7eb; color: #374151; }
.badge-issued { background: #dbeafe; color: #1d4ed8; }
.badge-partially_paid { background: #fef3c7; color: #b45309; }
.badge-paid { background: #dcfce7; color: #15803d; }
.badge-overdue { background: #fee2e2; color: #b91c1c; }
.badge-cancelled { background: #f3f4f6; color: #6b7280; text-decoration: line-through; }

/* ---------- Forms ---------- */
.form-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; max-width: 720px; }
.form-grid label { font-size: 13px; font-weight: 600; display: block; margin-bottom: 4px; }
.form-grid input, .form-grid select, .form-grid textarea { width: 100%; padding: 9px 11px; border: 1px solid var(--color-border); border-radius: var(--radius); font-size: 14px; }
.form-full { grid-column: 1 / -1; }

/* ---------- Invoice item rows ---------- */
.item-row-table { width: 100%; border-collapse: collapse; margin: 16px 0; }
.item-row-table th, .item-row-table td { padding: 8px; border-bottom: 1px solid var(--color-border); font-size: 13px; }
.item-autocomplete-wrap { position: relative; }
.item-autocomplete-results { position: absolute; top: 100%; left: 0; right: 0; background: #fff; border: 1px solid var(--color-border); border-radius: var(--radius); max-height: 220px; overflow-y: auto; z-index: 20; box-shadow: 0 8px 24px rgba(0,0,0,.1); }
.item-autocomplete-results div { padding: 8px 10px; cursor: pointer; font-size: 13px; }
.item-autocomplete-results div:hover { background: #f3f4f6; }
.totals-box { max-width: 320px; margin-left: auto; margin-top: 12px; font-size: 14px; }
.totals-box div { display: flex; justify-content: space-between; padding: 4px 0; }
.totals-box .grand-total { font-weight: 700; font-size: 16px; border-top: 1px solid var(--color-border); margin-top: 6px; padding-top: 8px; }

@media print {
  .sidebar, .topbar, .quick-actions, .btn { display: none !important; }
  .content { padding: 0; }
}