This could be refactored further:

#button {
  background: #68b12f;
  width: 120px;
  border: 1px solid #108211;
  border-radius: 3px;
  box-shadow: 0px 3px 9px black;
  margin: 0px 0px 10px 62.5px;
  a {
    color: black;
  }
  &:hover {
    opacity: 0.9;
  }
}