.form-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

.form-row label {
  display: block;
}

.form-row input,
.form-row select {
  width: 100%;
  box-sizing: border-box;
}

/* Responsive: en móvil una columna */
@media (max-width: 768px) {
  .form-row {
    grid-template-columns: 1fr;
  }
}

.form-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
.form-grid-3 {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1rem;
}
.form-section {
  background: #f9fafb;
  padding: 1rem 1.2rem;
  border-radius: 10px;
  border: 1px solid #e5e7eb;
  margin-bottom: 1.5rem;
}
.form-section h3 {
  margin-top: 0;
  margin-bottom: .7rem;
  font-weight: 600;
  color: #222;
}
.form-section label {
  font-size: .9rem;
  color: #333;
}
.form-section input,
.form-section select {
  width: 100%;
  margin-top: .3rem;
  padding: .55rem .7rem;
  border-radius: 6px;
  border: 1px solid #d1d5db;
}
fieldset.payment-box {
  border: 1px solid #e5e7eb;
  padding: 1rem;
  border-radius: 10px;
}