Flexbox

<div class="container">
  <a href="#">Register</a>
  <a href="#">Login</a>
</div>

.container {
  display: flex;
  flex-direction: column;
  width: 220px;
  padding: 30px;
  min-height: 300px;
  background-color: teal;
  text-align:center;
}
.container a{
  margin: 10px;
  padding: 12px;
  background-color: white;
  font-family: sans-serif;
  color: #333333;
  text-decoration: none;
  border-radius: 5px;
}


.container {
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 220px;
  padding: 30px;
  min-height: 300px;
  background-color: teal;
  text-align:center;
}
.container a{
  margin: 10px;
  padding: 12px;
  background-color: white;
  font-family: sans-serif;
  color: #333333;
  text-decoration: none;
  border-radius: 5px;
}
