* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", "Noto Sans Thai", sans-serif;
  background: #fafafa;
  color: #222;
}
#app {
  max-width: 420px;
  margin: 0 auto;
  padding: 16px;
  min-height: 100vh;
}
h1, h2 { margin: 8px 0 16px; }
.label { font-size: 13px; color: #888; margin: 8px 0; }
.big-number { font-size: 26px; font-weight: 800; }

.big-btn {
  display: block;
  width: 100%;
  border: none;
  border-radius: 16px;
  padding: 24px 16px;
  text-align: center;
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 14px;
  cursor: pointer;
}
.big-btn span { display: block; font-size: 13px; font-weight: 400; color: #555; margin-top: 4px; }
.big-btn.yellow { background: #fff3cd; border: 2px solid #ffc107; }
.big-btn.green { background: #d4edda; border: 2px solid #28a745; }
.big-btn.red { background: #f8d7da; border: 2px solid #dc3545; color: #721c24; }
.big-btn:disabled { opacity: 0.5; cursor: not-allowed; }

.ghost-btn, .undo-btn {
  width: 100%;
  padding: 10px;
  background: transparent;
  color: #888;
  border: 1px dashed #ccc;
  border-radius: 12px;
  font-size: 13px;
  margin-top: 8px;
  cursor: pointer;
}

.callout {
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 16px;
}
.callout.yellow { background: #fff3cd; }
.callout.green { background: #d4edda; }

.product-list, .basket-list, .credit-list {
  list-style: none;
  padding: 0;
  margin: 0 0 12px;
}
.product-list li, .basket-list li, .credit-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 8px;
  border-bottom: 1px solid #eee;
}
.credit-list li .owed { font-weight: 700; color: #dc3545; }

.product-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 16px;
}
.product-grid button {
  padding: 14px 6px;
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 10px;
  font-size: 15px;
}
.product-grid .price { color: #888; font-size: 12px; }

.toggle-row { display: flex; gap: 10px; margin-bottom: 16px; }
.toggle-row button {
  flex: 1;
  padding: 16px 8px;
  background: #fff;
  border: 2px solid #ddd;
  border-radius: 12px;
  color: #888;
  font-size: 15px;
}
.toggle-row button.selected { background: #e8f5e9; border-color: #28a745; color: #222; font-weight: 700; }

.denom-row { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 10px; }
.denom-row button {
  padding: 8px 14px;
  background: #fff;
  border: 1px solid #ccc;
  border-radius: 8px;
}
.denom-row button.selected { background: #fff3cd; border: 2px solid #ffc107; font-weight: 700; }

.mock-input {
  width: 100%;
  font-size: 16px;
  padding: 12px;
  margin-bottom: 14px;
  border: 1px solid #ccc;
  border-radius: 10px;
}

button { font-family: inherit; }