body.center {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-top: 30px;
  font-family: Arial, sans-serif;
}
main {
  width: 300px;
}
form div {
  margin-bottom: 1em;
}
label {
  font-weight: bold;
}
select, button {
  padding: 5px 10px;
  font-size: 1em;
}