body {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  text-align: center;
}
main {
  width: 500px;
}
form.entrar {
  padding: 20px 10px;
}
form.entrar .append {
  color: #AB0000;
  margin-top: 1rem;
  font-size: 15pt;
}