.ec-back-in-stock__button {
  margin: 10px 0px;
  font-size: 1.1rem;
  color: #000000;
  background-color: #ffffff;
  border: 1px solid;
  border-radius: 5px;
}

@media screen and (min-width: 800px) {

  .ec-back-in-stock__button {
    width: 31rem;
  }
}

@media screen and (max-width: 799px) {

  .ec-back-in-stock__button {
    width: 19rem;
  }
}