body {
  text-align: center;
  
  background-color: #f2f2f2;
}

input {
  padding: 10px;
  font-size: 16px;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  margin-left: 10px;
  cursor: pointer;
}

#mensaje {
  margin-top: 20px;
  font-size: 18px;
  font-weight: bold;
}