.shipping-shell {
  max-width: 960px;
  margin: 0 auto;
}
.shipping-grid {
  display: grid;
  grid-template-columns: minmax(0,1.5fr) minmax(260px,1fr);
  gap: 20px;
}
@media (max-width: 900px) {
  .shipping-grid {
    grid-template-columns: 1fr;
  }
}
.shipping-preview-box {
  border-radius: 18px;
  border: 1px solid rgba(148,163,184,0.55);
  background: #f9fafb;
  padding: 12px 14px;
}