.center {
    display: flex;
    justify-content: center;
    align-items: center;
}

button {
  background: linear-gradient(to bottom, #71ff8d, #00a437);
  color: #222;

  border: 1px solid #0a6000;
  border-top-color: #0a6000;
  border-left-color: #0a6000;
  border-bottom-color: #0a6000;
  border-right-color: #0a6000;

  padding: 6px 18px;
  border-radius: 3px;

  font-family: Arial, sans-serif;
  font-size: 14px;


  cursor: pointer;
}

button:hover {
  background: linear-gradient(to bottom, #71ff8d, #00a437);
}

button:active {
  background: linear-gradient(to bottom, #00a437, #71ff8d);
  border-top-color: #555;
  border-left-color: #555;
  border-bottom-color: #ddd;
  border-right-color: #ddd;
}

a {
  color: #0000EE;
  text-decoration: none;
}
a:visited {
  color: #0000EE;
  text-decoration: none;
}
a:hover {
  color: #0000EE;
  text-decoration: underline;
}