#box {
  width: 500px; padding: 10px;
  position: absolute; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  -webkit-transform: translate(-50%, -50%);
  border: 2px solid grey;
  text-align: center;
}
#box label {
  display: inline-block; width: 100px;
}

#box div {
  margin-bottom: 10px;
}

#box div:last-of-type {
  margin-bottom: 0px;
}

#box div input {
  padding: 10px; background-color: white; border: 1px solid grey;
}

#box #save {
  margin: 20px auto 0 auto;
}