.btn-flat-border {
  display: inline-block;
  padding: 0.3em 1em;
  text-decoration: none;
  color: #008000;
  border: solid 2px #008000;
  border-radius: 3px;
  transition: .4s;
  width: 100%;
}

.btn-flat-border:hover {
  background: #008000;
  color: white;
}

:disabled {
  background-color: #7F7F7F;
}