:root[data-theme="dark"] {
  --bg: #0f1115;
  --bg-elevated: #171a21;
  --bg-card: #1b1f27;
  --border: #2a2f3a;
  --text: #e6e9ef;
  --text-muted: #9aa3b2;
  --accent: #6366f1;
  --accent-2: #22c55e;
  --danger: #ef4444;
  --warning: #f59e0b;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
}

:root[data-theme="light"] {
  --bg: #f4f5f7;
  --bg-elevated: #ffffff;
  --bg-card: #ffffff;
  --border: #e2e5eb;
  --text: #1a1d24;
  --text-muted: #666e7d;
  --accent: #6366f1;
  --accent-2: #16a34a;
  --danger: #dc2626;
  --warning: #d97706;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

button, input, select { font-family: inherit; }

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 24px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 20;
}

.header-left { display: flex; align-items: center; gap: 10px; }
.header-left h1 { font-size: 18px; margin: 0; }
.logo { font-size: 22px; }
.header-right { display: flex; align-items: center; gap: 8px; }

.tabs { display: flex; gap: 4px; }
.tabs-mobile { display: none; padding: 8px 12px; background: var(--bg-elevated); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 19; overflow-x: auto; }

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  white-space: nowrap;
}
.tab-btn:hover { background: var(--bg-card); color: var(--text); }
.tab-btn.active { background: var(--accent); color: #fff; }

.btn {
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn:hover { border-color: var(--accent); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-danger { background: var(--danger); border-color: var(--danger); color: #fff; }
.btn-ghost { background: transparent; }
.btn-small { padding: 6px 10px; font-size: 13px; }
.btn-icon { padding: 8px 10px; }

main { padding: 20px 24px 60px; max-width: 1280px; margin: 0 auto; }

.tab-content { display: none; }
.tab-content.active { display: block; }

/* ---- period bar ---- */
.period-bar { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-bottom: 20px; }
.period-presets { display: flex; gap: 6px; flex-wrap: wrap; }
.period-btn {
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-muted);
  padding: 7px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 13px;
}
.period-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.custom-range { display: flex; align-items: center; gap: 8px; }
.custom-range.hidden { display: none; }
.custom-range input[type="date"] {
  background: var(--bg-card); color: var(--text); border: 1px solid var(--border);
  border-radius: 6px; padding: 6px 8px;
}

/* ---- stat cards ---- */
.stat-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-bottom: 20px; }
.stat-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 18px; box-shadow: var(--shadow);
}
.stat-label { color: var(--text-muted); font-size: 13px; margin-bottom: 6px; }
.stat-value { font-size: 26px; font-weight: 700; }
.stat-diff { font-size: 13px; margin-top: 6px; }
.stat-diff.up { color: var(--danger); }
.stat-diff.down { color: var(--accent-2); }

/* ---- charts ---- */
.chart-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.chart-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 18px; box-shadow: var(--shadow);
}
.chart-card h3 { margin: 0 0 12px; font-size: 15px; color: var(--text-muted); font-weight: 600; }
.chart-card.wide { grid-column: span 2; }
.chart-wrap { position: relative; height: 280px; }

.merchant-list { display: flex; flex-direction: column; gap: 10px; }
.merchant-row { display: flex; justify-content: space-between; align-items: center; font-size: 14px; }
.merchant-row .name { color: var(--text); }
.merchant-row .amount { color: var(--text-muted); font-variant-numeric: tabular-nums; }

/* ---- filters / table ---- */
.filters-bar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.filters-bar input, .filters-bar select {
  background: var(--bg-card); color: var(--text); border: 1px solid var(--border);
  border-radius: 8px; padding: 8px 10px; font-size: 13px;
}
.filters-bar input[type="number"] { width: 110px; }

.table-wrap { overflow-x: auto; background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px; }
table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 700px; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); white-space: nowrap; }
th { color: var(--text-muted); font-weight: 600; font-size: 12px; text-transform: uppercase; }
tbody tr:hover { background: var(--bg-elevated); }
.cat-chip { display: inline-flex; align-items: center; gap: 6px; padding: 3px 9px; border-radius: 14px; font-size: 12px; }
.row-actions { display: flex; gap: 6px; }
.row-actions button { background: transparent; border: none; cursor: pointer; font-size: 15px; color: var(--text-muted); }
.row-actions button:hover { color: var(--text); }

.pagination { display: flex; align-items: center; justify-content: center; gap: 16px; margin-top: 16px; font-size: 13px; color: var(--text-muted); }

/* ---- categories ---- */
.section-header { display: flex; justify-content: space-between; align-items: center; margin: 8px 0 16px; }
.backup-header { margin-top: 36px; }
.categories-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 14px; }
.category-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px; padding: 14px 16px; box-shadow: var(--shadow); }
.category-card-top { display: flex; justify-content: space-between; align-items: flex-start; }
.category-name { display: flex; align-items: center; gap: 8px; font-weight: 600; }
.category-actions { display: flex; gap: 4px; }
.category-actions button { background: transparent; border: none; cursor: pointer; color: var(--text-muted); }
.category-actions button:hover { color: var(--text); }
.progress-track { height: 8px; border-radius: 6px; background: var(--bg-elevated); margin-top: 12px; overflow: hidden; }
.progress-fill { height: 100%; border-radius: 6px; }
.progress-label { display: flex; justify-content: space-between; font-size: 12px; color: var(--text-muted); margin-top: 6px; }

.backup-actions { display: flex; gap: 10px; flex-wrap: wrap; }

/* ---- modal ---- */
.modal { position: fixed; inset: 0; background: rgba(0,0,0,0.55); display: flex; align-items: center; justify-content: center; z-index: 100; padding: 16px; }
.modal.hidden { display: none; }
.modal-content { background: var(--bg-elevated); border: 1px solid var(--border); border-radius: 14px; padding: 22px; width: 100%; max-width: 420px; box-shadow: var(--shadow); }
.modal-content h3 { margin-top: 0; }
.modal-content form { display: flex; flex-direction: column; gap: 12px; }
.modal-content label { display: flex; flex-direction: column; gap: 6px; font-size: 13px; color: var(--text-muted); }
.modal-content input, .modal-content select {
  background: var(--bg-card); color: var(--text); border: 1px solid var(--border);
  border-radius: 8px; padding: 9px 10px; font-size: 14px;
}
.modal-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 6px; }

.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: var(--bg-elevated); border: 1px solid var(--border); color: var(--text);
  padding: 12px 20px; border-radius: 10px; box-shadow: var(--shadow); z-index: 200; font-size: 14px;
}
.toast.hidden { display: none; }
.toast.error { border-color: var(--danger); color: var(--danger); }

/* ---- responsive ---- */
@media (max-width: 900px) {
  .app-header .tabs { display: none; }
  .tabs-mobile { display: flex; }
  .chart-grid { grid-template-columns: 1fr; }
  .chart-card.wide { grid-column: span 1; }
  .stat-cards { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .app-header { padding: 10px 14px; }
  .header-left h1 { display: none; }
  main { padding: 14px 12px 40px; }
  .filters-bar input, .filters-bar select { flex: 1 1 45%; }
}