:root {
  --bg: #f4f5f8;
  --card-bg: #ffffff;
  --border: #e4e7ec;
  --border-strong: #d3d8e0;
  --text: #1a1f2b;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #eef2ff;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --success: #16a34a;
  --success-soft: #ecfdf5;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.04);
  --shadow-md: 0 4px 14px rgba(16, 24, 40, 0.08);
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.muted { color: var(--muted); font-weight: normal; font-size: 0.85em; }

/* ---------- Who-are-you screen ---------- */
.who-screen {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 100;
}
.who-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 420px;
  width: 100%;
  text-align: center;
}
.who-buttons {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin: 16px 0;
  flex-wrap: wrap;
}
.who-buttons button {
  padding: 12px 20px;
  font-size: 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--primary);
  background: var(--card-bg);
  color: var(--primary);
  cursor: pointer;
}
.who-buttons button:hover { background: #eef2ff; }
.who-custom {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}
.who-custom input {
  flex: 1;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 1rem;
}

/* ---------- Layout ---------- */
.app { max-width: 1120px; margin: 0 auto; padding: var(--space-3) var(--space-3) 60px; }

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-1) var(--space-4);
}
.topbar h1 { font-size: 1.35rem; margin: 0; letter-spacing: -0.01em; }
.whoami {
  font-size: 0.85rem;
  color: var(--muted);
  background: var(--card-bg);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 999px;
}
.whoami strong { color: var(--text); }

.link-btn {
  background: none;
  border: none;
  color: var(--primary);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
  font-size: 0.85rem;
  padding: 0 0 0 8px;
}
.link-btn:hover { color: var(--primary-hover); }

.tabs {
  display: flex;
  gap: var(--space-1);
  margin-bottom: var(--space-4);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
}
.tab-btn {
  flex: 1;
  padding: 12px 8px 10px;
  border: none;
  background: none;
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  border-radius: 6px 6px 0 0;
  transition: color 0.15s ease, background-color 0.15s ease;
}
.tab-btn .tab-en { display: block; font-size: 0.72rem; font-weight: 400; margin-top: 1px; }
.tab-btn:hover { color: var(--text); background: rgba(37, 99, 235, 0.06); }
.tab-btn.active { color: var(--primary); border-bottom-color: var(--primary); }

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

.panel {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
  margin-bottom: var(--space-4);
}
.panel h2 { margin: 0 0 var(--space-3); font-size: 1.02rem; font-weight: 700; }
.panel-header-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}
.panel-header-row h2 { margin: 0; }

/* ---------- To Purchase: sticky cart panel + catalog ---------- */
.to-purchase-layout {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
}
.catalog-panel { flex: 1; min-width: 0; }
.cart-panel {
  flex: 0 0 320px;
  width: 320px;
  position: sticky;
  top: 56px;
  max-height: calc(100vh - 72px);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  padding: 0;
}
.cart-panel-toggle {
  display: none; /* only shown on mobile */
}
.cart-panel-body {
  padding: var(--space-4);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.cart-panel .panel-header-row { margin-bottom: 0; }
.btn-block { width: 100%; }

.cart-totals {
  border-top: 1px solid var(--border);
  padding-top: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.cart-totals-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.95rem;
}
.cart-totals-row strong { font-size: 1.1rem; }
.cart-totals-row-vp { color: var(--muted); font-size: 0.85rem; }
.cart-totals-row-vp strong { font-size: 0.95rem; color: var(--text); }

/* ---------- Search / catalog ---------- */
.search-box {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 1rem;
  margin-bottom: 12px;
}

.category-group { margin-bottom: var(--space-2); }
.category-title {
  font-weight: 700;
  font-size: 0.92rem;
  letter-spacing: 0.01em;
  padding: 10px 12px;
  margin-bottom: 6px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
  background: var(--primary-soft);
  border-radius: var(--radius-sm);
  user-select: none;
  transition: background-color 0.15s ease;
}
.category-title:hover { background: #e2e9fd; }
.category-title span:last-child { color: var(--primary); font-size: 0.8rem; }
.category-body { display: flex; flex-direction: column; gap: 8px; padding-bottom: 4px; }
.category-body.collapsed { display: none; }

.product-card {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  background: var(--card-bg);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.product-card:hover { border-color: var(--border-strong); box-shadow: var(--shadow-sm); }
.product-main { flex: 1; min-width: 180px; }
.product-name { font-weight: 600; font-size: 0.96rem; }
.product-meta { font-size: 0.82rem; color: var(--muted); display: flex; flex-wrap: wrap; gap: 8px; margin-top: 4px; }
.product-meta input {
  border: 1px dashed var(--border);
  background: transparent;
  font-size: 0.82rem;
  color: var(--muted);
  padding: 3px 6px;
  border-radius: 5px;
  width: 110px;
}
.product-meta input.alias-input { width: 190px; }
.product-meta input:hover { border-color: var(--border-strong); background: var(--bg); }
.product-meta input:focus {
  border-color: var(--primary);
  border-style: solid;
  background: var(--card-bg);
  outline: none;
}
.product-price { font-weight: 700; min-width: 74px; text-align: right; font-variant-numeric: tabular-nums; }
.add-controls { display: flex; align-items: center; gap: 8px; }
.add-controls input[type="number"] {
  width: 54px;
  padding: 7px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  text-align: center;
  font-size: 0.9rem;
}
.add-controls input[type="number"]:focus { border-color: var(--primary); outline: none; }

/* ---------- Buttons ---------- */
.btn {
  padding: 9px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--card-bg);
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.05s ease;
}
.btn:hover { background: #eef0f3; border-color: #c3c9d3; }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; transform: none; }
.btn-primary { background: var(--primary); border-color: var(--primary); color: #fff; box-shadow: 0 1px 2px rgba(37,99,235,0.25); }
.btn-primary:hover:not(:disabled) { background: var(--primary-hover); border-color: var(--primary-hover); }
.btn-sm { padding: 6px 11px; font-size: 0.8rem; }
.btn-danger { color: var(--danger); border-color: #f3c6c6; background: var(--card-bg); }
.btn-danger:hover { background: var(--danger-soft); border-color: var(--danger); }

/* ---------- Cart / purchased list ---------- */
.cart-list { display: flex; flex-direction: column; gap: 8px; }
.cart-item {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 12px;
  background: var(--card-bg);
  transition: border-color 0.15s ease;
}
.cart-item:hover { border-color: var(--border-strong); }
.cart-item-main { flex: 1; min-width: 140px; }
.cart-item-name { font-weight: 600; font-size: 0.92rem; }
.cart-item-meta { font-size: 0.78rem; color: var(--muted); margin-top: 2px; }
.qty-stepper { display: flex; align-items: center; gap: 4px; }
.qty-stepper button {
  width: 28px; height: 28px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  transition: background-color 0.15s ease;
}
.qty-stepper button:hover { background: var(--primary-soft); border-color: var(--primary); color: var(--primary); }
.qty-stepper input {
  width: 44px;
  text-align: center;
  padding: 5px;
  border: 1px solid var(--border);
  border-radius: 6px;
}
.line-total { font-weight: 700; min-width: 70px; text-align: right; font-variant-numeric: tabular-nums; }
.empty-note { color: var(--muted); padding: 16px 8px; font-size: 0.88rem; text-align: center; }

.shipped-badge {
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: #ecfdf5;
  color: var(--success);
  border: 1px solid #a7f3d0;
}
.unshipped-badge {
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: #fef2f2;
  color: var(--danger);
  border: 1px solid #fecaca;
}

/* ---------- Shipments ---------- */
.shipment-group {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 10px;
  overflow: hidden;
}
.shipment-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  background: #fafbfc;
  cursor: pointer;
  flex-wrap: wrap;
}
.shipment-header-title { font-weight: 600; }
.shipment-header-link { font-size: 0.85rem; }
.shipment-body { padding: 10px 12px; display: flex; flex-direction: column; gap: 8px; }
.shipment-body.collapsed { display: none; }
.shipment-edit-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
}
.shipment-edit-row input {
  flex: 1;
  min-width: 140px;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
}

/* ---------- Modal ---------- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  z-index: 200;
}
.modal {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px;
  max-width: 420px;
  width: 100%;
}
.modal h3 { margin-top: 0; }
.modal label { display: block; margin: 10px 0 4px; font-size: 0.9rem; }
.modal input[type="text"], .modal select {
  width: 100%;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
}
.field-row { display: flex; flex-direction: column; gap: 6px; margin-bottom: 6px; font-size: 0.9rem; }
.modal-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 16px; }

.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: #1f2430;
  color: #fff;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 0.9rem;
  z-index: 300;
}

input[type="checkbox"] { width: 18px; height: 18px; cursor: pointer; accent-color: var(--primary); }

/* ---------- Mobile: collapse cart to a summary bar above the catalog ---------- */
@media (max-width: 760px) {
  .to-purchase-layout { flex-direction: column; }
  .cart-panel {
    position: static;
    width: 100%;
    flex: none;
    max-height: none;
    box-shadow: var(--shadow-md);
  }
  .cart-panel-toggle {
    display: flex;
    width: 100%;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    padding: var(--space-3) var(--space-4);
    background: var(--card-bg);
    border: none;
    border-bottom: 1px solid var(--border);
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text);
    cursor: pointer;
  }
  .cart-panel-toggle-summary { flex: 1; text-align: right; font-weight: 500; color: var(--muted); font-size: 0.82rem; }
  .cart-panel-toggle-chevron { color: var(--primary); transition: transform 0.15s ease; }
  .cart-panel.collapsed .cart-panel-toggle-chevron { transform: rotate(-90deg); }
  .cart-panel.collapsed .cart-panel-body { display: none; }
  .cart-panel-body { max-height: 60vh; }
}

@media (max-width: 480px) {
  .app { padding: 8px; }
  .topbar h1 { font-size: 1.1rem; }
  .cart-item, .product-card { flex-direction: column; align-items: stretch; }
  .line-total, .product-price { text-align: left; }
}