body {
  background-color:lightseagreen;
}
h1 {
  color:violet; font-family:verdana;
}

/* This was missing from the code */
#result {
  background-color: white;
}
#container {
  position: fixed;
  top: 50%;
  left: 50%;
  transform:translate(-50%, -55%);
  background-color:purple;
  border-radius: 4%;
  padding: 20px;
}