:root {
  /* Dark theme palette */
  --bg: #0d1117;
  --bg-elev: #141a23;
  --surface: #1a212c;
  --surface-2: #232c3a;
  --border: #2a3447;
  --border-strong: #3a4660;
  --text: #e6ecf5;
  --text-muted: #8b96ad;
  --text-subtle: #5b667c;

  /* Silk blue gradient accent */
  --silk-1: #4a7fa7;
  --silk-2: #6fa8d6;
  --silk-3: #9ec9ec;
  --silk-glow: rgba(111, 168, 214, 0.18);
  --gradient-silk: linear-gradient(135deg, #3d6f96 0%, #5b9bd5 50%, #8fb8dc 100%);
  --gradient-silk-soft: linear-gradient(135deg, rgba(91,155,213,0.12) 0%, rgba(143,184,220,0.08) 100%);

  /* Status colors */
  --ok: #4ade80;
  --warn: #fbbf24;
  --danger: #f87171;
  --danger-strong: #ef4444;

  --radius: 10px;
  --radius-sm: 6px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.55);
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 14px;
  -webkit-font-smoothing: antialiased;
}
body {
  min-height: 100vh;
  background-image:
    radial-gradient(at 15% 0%, rgba(91, 155, 213, 0.08) 0%, transparent 40%),
    radial-gradient(at 85% 0%, rgba(74, 127, 167, 0.06) 0%, transparent 45%);
  background-attachment: fixed;
}
.hidden { display: none !important; }
.muted { color: var(--text-muted); font-size: 0.9em; }
.error { color: var(--danger); min-height: 1.2em; margin: 6px 0 0; font-size: 0.9em; }

/* Auth screen */
.auth-screen {
  position: fixed; inset: 0;
  display: flex; align-items: center; justify-content: center;
  background:
    radial-gradient(at 30% 20%, rgba(91, 155, 213, 0.12) 0%, transparent 50%),
    radial-gradient(at 70% 80%, rgba(74, 127, 167, 0.10) 0%, transparent 50%),
    var(--bg);
}
.auth-card {
  width: 360px;
  background: var(--surface);
  padding: 32px 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}
.auth-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--gradient-silk);
}
.auth-card h1 {
  margin: 0 0 6px;
  font-size: 24px;
  background: var(--gradient-silk);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 600;
  letter-spacing: -0.3px;
}
.auth-card input {
  display: block; width: 100%;
  padding: 11px 12px; margin: 12px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-elev);
  color: var(--text);
  font-size: 14px;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.auth-card input:focus {
  outline: none;
  border-color: var(--silk-2);
  box-shadow: 0 0 0 3px var(--silk-glow);
}
.auth-card button {
  width: 100%;
  padding: 11px;
  background: var(--gradient-silk);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 0.2px;
  transition: transform 0.1s, box-shadow 0.15s;
}
.auth-card button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(91, 155, 213, 0.3);
}

/* App header */
.app-header {
  display: flex; align-items: center; gap: 14px;
  padding: 12px 18px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: relative;
  z-index: 10;
}
.app-header::after {
  content: '';
  position: absolute; left: 0; right: 0; bottom: -1px;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--silk-2) 50%, transparent 100%);
  opacity: 0.4;
}
.brand { display: flex; align-items: baseline; gap: 8px; flex-shrink: 0; }
.brand strong {
  font-size: 16px;
  background: var(--gradient-silk);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 600;
}
.page-title {
  margin-left: auto;
  font-size: 14px;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* Hamburger button */
.hamburger-btn {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 38px; height: 38px;
  padding: 9px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  flex-shrink: 0;
  transition: all 0.15s;
}
.hamburger-btn:hover {
  border-color: var(--silk-2);
  background: var(--surface-2);
}
.hamburger-btn span {
  display: block;
  height: 2px;
  background: var(--text);
  border-radius: 1px;
  transition: background 0.15s;
}
.hamburger-btn:hover span { background: var(--silk-3); }

/* Nav drawer */
.nav-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(3px);
  z-index: 90;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.22s ease;
}
.nav-backdrop.open { opacity: 1; pointer-events: auto; }

.nav-drawer {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: 280px;
  max-width: 80vw;
  background: var(--surface);
  border-right: 1px solid var(--border);
  z-index: 100;
  transform: translateX(-100%);
  transition: transform 0.22s ease;
  box-shadow: 4px 0 20px rgba(0, 0, 0, 0.3);
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow-y: auto;
}
.nav-drawer.open { transform: translateX(0); }
.nav-drawer-header {
  padding: 18px 20px 14px;
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
  border-bottom: 1px solid var(--border);
  background: var(--gradient-silk-soft);
  position: relative;
}
.nav-drawer-header::after {
  content: '';
  position: absolute; left: 0; right: 0; bottom: -1px;
  height: 2px;
  background: var(--gradient-silk);
}
.nav-list {
  display: flex;
  flex-direction: column;
  padding: 8px 8px;
  gap: 2px;
}
.nav-item {
  display: block;
  padding: 12px 14px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  text-align: left;
  width: 100%;
  font-size: 14px;
  color: var(--text);
  cursor: pointer;
  transition: all 0.12s;
  font-weight: 500;
}
.nav-item:hover {
  background: var(--surface-2);
  border-color: var(--border);
}
.nav-item.active {
  background: var(--gradient-silk);
  color: white;
  border-color: transparent;
  box-shadow: 0 2px 10px rgba(91, 155, 213, 0.35);
}

.ghost-btn {
  background: transparent;
  border: 1px solid var(--border);
  padding: 7px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
  transition: all 0.15s;
}
.ghost-btn:hover { background: var(--surface-2); border-color: var(--border-strong); }
.primary-btn {
  background: var(--gradient-silk);
  color: white;
  border: none;
  padding: 9px 18px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  transition: all 0.15s;
  letter-spacing: 0.2px;
}
.primary-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 14px rgba(91, 155, 213, 0.35); }
.danger-btn {
  background: var(--danger-strong);
  color: white;
  border: none;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 12px;
}

main { padding: 20px; max-width: 1320px; margin: 0 auto; }
.tab-panel { display: none; }
.tab-panel.active { display: block; }
.hide-mobile { display: inline; }

/* Table scroll wrapper — keeps wide tables from blowing out layout on mobile */
.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: var(--radius);
  max-width: 100%;
}
.table-scroll .data-table {
  margin: 12px 0;
  min-width: 560px;
}
h2 {
  margin: 0 0 16px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.2px;
}
h3 {
  margin: 28px 0 10px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 0.1px;
}

/* Stat cards */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px;
  margin: 14px 0;
}
.stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
  transition: transform 0.15s, border-color 0.15s;
}
.stat::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--gradient-silk);
  opacity: 0.7;
}
.stat:hover { transform: translateY(-1px); border-color: var(--border-strong); }
.stat-label {
  color: var(--text-muted);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}
.stat-value {
  font-size: 24px;
  font-weight: 700;
  margin-top: 6px;
  color: var(--text);
  letter-spacing: -0.5px;
}

/* Forms */
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin: 14px 0;
}
.form-grid label, .form-field {
  display: flex; flex-direction: column;
  font-size: 11px;
  color: var(--text-muted);
  gap: 5px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}
.form-grid input, .form-grid select, .form-grid textarea, .form-field input, .form-field select, .form-field textarea {
  font-size: 14px;
  color: var(--text);
  padding: 9px 11px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-elev);
  font-family: inherit;
  text-transform: none;
  letter-spacing: normal;
  font-weight: normal;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.form-grid input:focus, .form-grid select:focus, .form-grid textarea:focus,
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  outline: none;
  border-color: var(--silk-2);
  box-shadow: 0 0 0 3px var(--silk-glow);
}
textarea { min-height: 64px; resize: vertical; }
.form-actions { margin: 18px 0; display: flex; gap: 10px; }

/* Line items inside invoice form */
.line-items { width: 100%; border-collapse: collapse; margin: 12px 0; }
.line-items th, .line-items td {
  padding: 7px 6px;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
  text-align: left;
  font-size: 13px;
}
.line-items th {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  font-weight: 600;
}
.line-items th.num, .line-items td.num { text-align: right; }
.line-items input, .line-items select {
  width: 100%;
  padding: 7px 9px;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--bg-elev);
  color: var(--text);
  font-size: 13px;
  font-family: inherit;
}
.line-items input:focus, .line-items select:focus {
  outline: none;
  border-color: var(--silk-2);
  box-shadow: 0 0 0 2px var(--silk-glow);
}
.line-items td.num input { text-align: right; font-variant-numeric: tabular-nums; }

.totals-row {
  display: flex; gap: 28px; margin: 14px 0;
  font-size: 14px;
  justify-content: flex-end;
  padding: 12px 16px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}
.total-line { font-weight: 700; font-size: 17px; color: var(--silk-3); }

/* Tables */
.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 12px 0;
}
.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(--surface-2);
  font-weight: 600;
  color: var(--text-muted);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tbody tr:hover { background: var(--surface-2); }

.filter-bar { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin: 12px 0; }
.filter-bar input, .filter-bar select {
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  background: var(--bg-elev);
  color: var(--text);
  font-family: inherit;
}
.filter-bar input:focus, .filter-bar select:focus {
  outline: none;
  border-color: var(--silk-2);
  box-shadow: 0 0 0 3px var(--silk-glow);
}

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.2px;
}
.badge.paid { background: rgba(74, 222, 128, 0.15); color: var(--ok); border: 1px solid rgba(74, 222, 128, 0.3); }
.badge.unpaid { background: rgba(251, 191, 36, 0.15); color: var(--warn); border: 1px solid rgba(251, 191, 36, 0.3); }
.badge.void { background: rgba(248, 113, 113, 0.15); color: var(--danger); border: 1px solid rgba(248, 113, 113, 0.3); }

.row-actions { display: flex; gap: 4px; flex-wrap: wrap; }
.row-actions button {
  padding: 5px 10px;
  font-size: 12px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.12s;
}
.row-actions button:hover {
  background: var(--surface-2);
  border-color: var(--silk-2);
  color: var(--silk-3);
}

/* Inventory category group rows */
.inv-group-row { background: var(--surface-2) !important; }
.inv-group-row:hover { background: var(--surface-2) !important; }
.inv-group-row td {
  padding: 10px 14px !important;
  border-top: 2px solid transparent;
  border-bottom: 1px solid var(--border) !important;
  background: linear-gradient(90deg, rgba(91,155,213,0.08) 0%, transparent 100%);
}
.inv-group-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 700;
  color: var(--silk-3);
}
.inv-group-count {
  margin-left: 12px;
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.05em;
}

/* Modal */
.modal-root { position: fixed; inset: 0; display: flex; align-items: center; justify-content: center; z-index: 100; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(0, 0, 0, 0.65); backdrop-filter: blur(4px); }
.modal {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  width: min(700px, 92vw);
  max-height: 90vh;
  overflow: auto;
  box-shadow: var(--shadow-lg);
}
.modal::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  border-radius: var(--radius) var(--radius) 0 0;
  background: var(--gradient-silk);
}
.modal h3 { margin-top: 0; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 18px; }

/* Selection color */
::selection { background: rgba(91, 155, 213, 0.35); color: var(--text); }

/* Scrollbars */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--surface-2); border-radius: 5px; border: 2px solid var(--bg); }
::-webkit-scrollbar-thumb:hover { background: var(--border-strong); }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 720px) {
  main { padding: 14px; }
  .app-header { padding: 10px 14px; gap: 10px; }
  .brand strong { font-size: 15px; }
  .hide-mobile { display: none; }
  .page-title { font-size: 12px; }

  h2 { font-size: 18px; }
  h3 { font-size: 14px; margin-top: 20px; }

  .stat-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .stat { padding: 12px 14px; }
  .stat-value { font-size: 19px; }

  .form-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
  .form-grid textarea { grid-column: 1 / -1; }

  .filter-bar { gap: 8px; }
  .filter-bar input, .filter-bar select { flex: 1; min-width: 130px; }

  .line-items th, .line-items td { padding: 5px 4px; font-size: 12px; }
  .data-table th, .data-table td { padding: 8px 8px; font-size: 12px; }

  .totals-row { flex-wrap: wrap; gap: 12px; padding: 10px 12px; }

  .modal { padding: 18px; }
  .modal-actions { flex-wrap: wrap; }

  .row-actions button { padding: 4px 8px; font-size: 11px; }
}

@media (max-width: 480px) {
  .stat-grid { grid-template-columns: 1fr; }
  .form-grid { grid-template-columns: 1fr; }
  .brand .muted { display: none; }
  .page-title { display: none; }
}

/* ============================================================
   PRINT STYLES — invoice always renders LIGHT for paper printing
   ============================================================ */
#print-area { display: none; }
@media print {
  @page { margin: 0.4in; size: letter; }
  body * { visibility: hidden; }
  #print-area, #print-area * { visibility: visible; }
  #print-area {
    display: block;
    position: absolute;
    inset: 0;
    padding: 0;
    background: white;
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: #1a1a1a;
  }
  .print-invoice {
    font-size: 10.5pt;
    line-height: 1.5;
    color: #1a1a1a;
    width: 100%;
    max-width: 100%;
    margin: 0;
    padding: 0;
  }

  .pi-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding-bottom: 14pt;
    border-bottom: 3pt solid #4a7fa7;
    margin-bottom: 22pt;
  }
  .pi-brand-name {
    font-size: 22pt;
    font-weight: 700;
    letter-spacing: -0.5pt;
    color: #4a7fa7;
    line-height: 1.1;
  }
  .pi-brand-sub {
    font-size: 9pt;
    color: #6b7368;
    margin-top: 4pt;
    letter-spacing: 0.2pt;
  }
  .pi-invoice-mark { text-align: right; }
  .pi-invoice-label {
    font-size: 9pt;
    letter-spacing: 3pt;
    color: #6b7368;
    text-transform: uppercase;
  }
  .pi-invoice-number {
    font-size: 24pt;
    font-weight: 700;
    color: #1a1a1a;
    margin-top: 2pt;
    line-height: 1;
  }

  .pi-meta {
    display: grid;
    grid-template-columns: 1.2fr 0.7fr 1.4fr;
    gap: 22pt;
    margin-bottom: 22pt;
  }
  .pi-meta-block { font-size: 10pt; }
  .pi-meta-label {
    font-size: 8pt;
    letter-spacing: 1.5pt;
    text-transform: uppercase;
    color: #6b7368;
    margin-bottom: 4pt;
    font-weight: 700;
  }
  .pi-meta-value { color: #1a1a1a; }
  .pi-meta-value div { line-height: 1.4; }
  .pi-bill-to .pi-bill-name {
    font-size: 12pt;
    font-weight: 700;
    margin-bottom: 2pt;
  }
  .pi-meta-stack-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16pt;
  }
  .pi-terms-pill {
    display: inline-block;
    padding: 3pt 11pt;
    background: #e3eef7;
    color: #4a7fa7;
    border-radius: 3pt;
    font-weight: 700;
    font-size: 10pt;
    letter-spacing: 0.5pt;
  }

  .pi-items {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 14pt;
  }
  .pi-items thead th {
    text-align: left;
    font-size: 8pt;
    letter-spacing: 1.5pt;
    text-transform: uppercase;
    color: #6b7368;
    font-weight: 700;
    padding: 8pt 6pt;
    border-bottom: 1.5pt solid #1a1a1a;
  }
  .pi-items .pi-col-num { text-align: right; }
  .pi-items tbody td {
    padding: 8pt 6pt;
    border-bottom: 0.5pt solid #e2e5dd;
    font-size: 10.5pt;
    vertical-align: top;
  }
  .pi-items tbody tr:last-child td { border-bottom: 1pt solid #1a1a1a; }
  .pi-items tfoot .pi-items-foot td {
    padding: 9pt 6pt 14pt 6pt;
    border-bottom: none;
    font-size: 11pt;
  }
  .pi-items .pi-col-desc { width: 55%; }
  .pi-col-num { text-align: right; font-variant-numeric: tabular-nums; }

  .pi-summary {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 18pt;
  }
  .pi-totals {
    border-collapse: collapse;
    font-size: 10.5pt;
    min-width: 3.2in;
  }
  .pi-totals td { padding: 4pt 0; }
  .pi-totals-label { color: #6b7368; text-align: right; padding-right: 18pt; }
  .pi-totals-num {
    text-align: right;
    font-variant-numeric: tabular-nums;
    color: #1a1a1a;
    min-width: 1.5in;
  }
  .pi-totals-grand td {
    border-top: 1.5pt solid #1a1a1a;
    padding-top: 10pt;
    padding-bottom: 4pt;
    font-size: 14pt;
    font-weight: 700;
    color: #1a1a1a;
  }
  .pi-totals-grand .pi-totals-label,
  .pi-totals-grand .pi-totals-num { color: #1a1a1a; }
  .pi-totals-balance td {
    border-top: 0.5pt solid #ccc;
    padding-top: 6pt;
    font-size: 12pt;
    font-weight: 700;
    color: #b93a2c;
  }

  .pi-notes-area {
    margin-top: 16pt;
    font-size: 9.5pt;
    color: #444;
    max-width: 4.5in;
  }
  .pi-notes-label {
    font-size: 8pt;
    letter-spacing: 1.5pt;
    text-transform: uppercase;
    color: #6b7368;
    font-weight: 700;
    margin-bottom: 4pt;
  }
  .pi-notes-body {
    padding: 8pt 12pt;
    border-left: 2pt solid #4a7fa7;
    background: #f4f7fb;
  }
}