.braintree{
  #card-number {
    height: 24px;
  }
  #card-number.braintree-hosted-fields-focused {
    border-color: #777;
  }
  #card-number.braintree-hosted-fields-invalid {
    border-color: tomato;
  }
  #card-number.braintree-hosted-fields-valid {
    border-color: limegreen;
  }
  #cvv {
    height: 24px;
  }
  #expiration-date {
    height: 24px;
  }
}