#game {
  position: absolute;
  width: 600px;
  height: 600px;
  top: 50%;
  left: 50%;
  margin-left: -300px;
  margin-top: -300px;
  border: 2px solid black;
}

#best-thought {
  position: absolute;
  margin: 0;
  margin-top: -10px;
  padding: 0;
}

#save-code {
  position: absolute;
  right: 10px;
}