.newsletter-inner {
  display: table;
  width: 100%;
  height: 100%;
}

.newsletter-middle {
  display: table-row;
}

.newsletter-middle > div {
  display: table-cell;
  vertical-align: middle;
  float: none;
}
@media (max-width: 767px) {
  .newsletter-middle > div {
    display: block;
    width: 100%;
    text-align: center;
  }
}