.rp-checkout-phone,.rp-checkout-coupon {
  display: grid;
  gap: .5rem;
  align-items: stretch;
}
.rp-checkout-phone { grid-template-columns: minmax(0, 46%) minmax(0, 1fr); }
.rp-checkout-coupon { grid-template-columns: minmax(0, 1fr) auto; }
.rp-checkout-phone > :is(input, select), .rp-checkout-coupon > input {
  box-sizing: border-box;
  min-width: 0;
  width: 100%;
}
@media (max-width: 420px) {
  .rp-checkout-phone, .rp-checkout-coupon { grid-template-columns: minmax(0, 1fr); }
}