:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --border: #e2e8f0;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --hardware: #d97706;
  --hardware-bg: #fef3c7;
  --grocery: #2563eb;
  --grocery-bg: #dbeafe;
  --sale: #16a34a;
  --sale-bg: #dcfce7;
  --warn: #d97706;
  --warn-bg: #fef3c7;
  --danger: #dc2626;
  --text: #1e293b;
  --muted: #64748b;
  --radius: 10px;
}

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

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

/* NAV */
nav {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 32px;
  height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--primary);
  text-decoration: none;
}
.nav-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  cursor: pointer;
}
.nav-link.active, .nav-link:hover {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* CATEGORY SWITCHER */
.category-bar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 0;
  padding: 0 24px;
  position: sticky;
  top: 56px;
  z-index: 99;
}
.cat-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  font-size: 0.9rem;
  font-weight: 600;
  border: none;
  background: none;
  cursor: pointer;
  color: var(--muted);
  border-bottom: 3px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}
.cat-btn:hover { color: var(--text); }
.cat-btn.active-grocery {
  color: var(--grocery);
  border-bottom-color: var(--grocery);
}
.cat-btn.active-hardware {
  color: var(--hardware);
  border-bottom-color: var(--hardware);
}
.cat-icon { font-size: 1.1rem; }
.cat-count {
  background: var(--border);
  border-radius: 99px;
  padding: 1px 7px;
  font-size: 0.72rem;
  font-weight: 700;
}
.active-grocery .cat-count { background: var(--grocery-bg); color: var(--grocery); }
.active-hardware .cat-count { background: var(--hardware-bg); color: var(--hardware); }

/* LAYOUT */
main { max-width: 1100px; margin: 0 auto; padding: 32px 24px; }

.page { display: none; }
.page.active { display: block; }

/* STATS */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}
.stat-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}
.stat-card .value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
}
.stat-card .label {
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 4px;
}

/* TOOLBAR */
.toolbar {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.toolbar input, .toolbar select {
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.9rem;
  background: var(--card);
  color: var(--text);
}
.toolbar input { min-width: 200px; }

/* PRODUCT GRID */
.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}
.product-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition: box-shadow 0.15s, transform 0.15s;
}
.product-card:hover {
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
  transform: translateY(-2px);
}
.product-card .thumb {
  width: 100%;
  height: 140px;
  object-fit: contain;
  background: #f1f5f9;
  padding: 8px;
}
.product-card .thumb-placeholder {
  width: 100%;
  height: 140px;
  background: #f1f5f9;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: #cbd5e1;
}
.product-card .body { padding: 14px; }
.product-card .store-badge {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}
.product-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.price-row {
  display: flex;
  align-items: baseline;
  gap: 8px;
}
.price-current {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
}
.price-original {
  font-size: 0.85rem;
  color: var(--muted);
  text-decoration: line-through;
}
.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 99px;
  font-size: 0.72rem;
  font-weight: 600;
}
.badge-sale { background: var(--sale-bg); color: var(--sale); }
.badge-target { background: var(--warn-bg); color: var(--warn); }
.product-card .footer {
  padding: 8px 14px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.product-card .footer .date {
  font-size: 0.75rem;
  color: var(--muted);
}

/* BUTTONS */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  border: none;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-outline {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-outline:hover { background: var(--bg); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-sm { padding: 5px 12px; font-size: 0.82rem; }

/* FORMS */
.form-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 620px;
}
.form-card h2 { margin-bottom: 24px; }
.form-group { margin-bottom: 18px; }
.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 6px;
  color: var(--muted);
}
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.9rem;
  background: var(--card);
  color: var(--text);
  transition: border-color 0.15s;
}
.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
}

/* SEARCH RESULTS */
.search-results { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.search-result-item {
  display: flex;
  gap: 14px;
  align-items: center;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  cursor: pointer;
  transition: border-color 0.15s;
}
.search-result-item:hover, .search-result-item.selected {
  border-color: var(--primary);
}
.search-result-item img {
  width: 56px;
  height: 56px;
  object-fit: contain;
  border-radius: 4px;
  background: #f1f5f9;
}
.search-result-item .info { flex: 1; }
.search-result-item .info .name { font-weight: 600; font-size: 0.9rem; }
.search-result-item .info .sub { font-size: 0.8rem; color: var(--muted); margin-top: 2px; }
.search-result-item .price { font-weight: 700; font-size: 1rem; white-space: nowrap; }

/* DETAIL PAGE */
.detail-header {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 24px;
}
.detail-header img {
  width: 120px;
  height: 120px;
  object-fit: contain;
  background: #f1f5f9;
  border-radius: 8px;
  padding: 8px;
}
.detail-header .info { flex: 1; }
.detail-header .info h2 { margin-bottom: 8px; }
.detail-header .info .store { color: var(--muted); font-size: 0.85rem; }
.chart-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 24px;
}
.chart-card h3 { margin-bottom: 16px; }

/* SALE TIMELINE */
.sale-timeline { display: flex; flex-direction: column; gap: 8px; margin-top: 12px; }
.sale-event {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 0.87rem;
}
.sale-event.on-sale { background: var(--sale-bg); }
.sale-event.normal { background: #f8fafc; border: 1px solid var(--border); }
.sale-event .dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}
.sale-event.on-sale .dot { background: var(--sale); }
.sale-event.normal .dot { background: var(--muted); }

/* EMPTY STATE */
.empty {
  text-align: center;
  padding: 60px 20px;
  color: var(--muted);
}
.empty .icon { font-size: 3rem; margin-bottom: 12px; }

/* TOAST */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--text);
  color: #fff;
  padding: 12px 20px;
  border-radius: 8px;
  font-size: 0.9rem;
  z-index: 999;
  opacity: 0;
  transform: translateY(8px);
  transition: all 0.25s;
  pointer-events: none;
}
.toast.show { opacity: 1; transform: translateY(0); }

/* LOADING */
.spinner {
  display: inline-block;
  width: 18px; height: 18px;
  border: 2px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Receipt items table */
.receipt-items-table input {
  font-family: inherit;
}
.receipt-items-table input:focus {
  border-color: var(--primary);
  outline: none;
}

@media (max-width: 600px) {
  main { padding: 16px; }
  .detail-header { flex-direction: column; }
}