body {
  text-align: center;
  font-family: Tahoma, Geneva, sans-serif;
}
hr {
  width: 550px;
}
div {
  margin-left: auto;
  margin-right: auto;
  text-align: left;
}
p {
  margin-left: auto;
  margin-right: auto;
}
input {
  border: solid 1px #000000;
  font-family: Tahoma, Geneva, sans-serif;
  font-size: 0.9em;
}
select {
  width: auto;
  border: solid 1px #000000;
  font-family: Tahoma, Geneva, sans-serif;
  font-size: 0.9em;
}
span {
  display: inline-block;
}
span.error {
  color: #ff0000;
}

@media only screen and (min-device-width: 512px) {
  body {
    font-size: 14px;
  }
  hr {
    width: 550px;
  }
  div {
    width: 500px;
    margin: 10px auto;
  }
  p {
    margin: 3px auto;
  }
  input {
    width: 45px;
  }
  span.label {
    width: 250px;
  }
}

@media only screen and (max-device-width: 512px) {
  body {
    font-size: 25px;
  }
  hr {
    width: 95%;
  }
  div {
    width: 90%;
    margin: 0.75em auto;
  }
  p {
    margin: 0.25em auto;
  }
  input {
    width: auto;
  }
  span.label {
    width: 50%;
  }
}