.fields {max-width: 100%;font-size: 1.6vw;padding: 1vw; text-align: center; background-color: #DCDCDC; color: #333333;}
.button{width: 100%; background-color: #FF0000; color: #FFFFFF;font-size: 1.8vw;padding: 1vw;letter-spacing: 2px; font-weight: 400;}
.form-group{margin-bottom: 20px;}
#contenedor {max-width: 100%;}
#contenedor > div {
  float: none;
  max-width: 100%;
  margin: 0 auto;
  width: 45%;
  padding: 5.5vw 20px 11vw;
}
@media screen and (max-width: 800px) {
  .fields {font-size: 18px; padding: 8px 20px;}
  .button{font-size: 20px; padding: 10px 20px;}
  .form-group{margin-bottom: 15px;}
  #contenedor > div {
    width: 100%; padding: 30px 25px 50px 25px;
  }
}