.sustainability_btn {
  width: 500px;
  margin: 50px auto 0;
}

@media screen and (max-width: 750px) {
  .sustainability_btn {
    width: 100%;
  }
}

.sustainability_btn > li {
  margin-bottom: 20px;
}

.sustainability_btn > li a {
  font-size: 1.7rem;
}