body {
  background-color: yellow;
}
div {
  margin: auto;
  width: 50%;
  border: 2px solid black;
  margin-top: 20%;
  padding: 15px;
  border-radius: 20px;
  box-shadow: 5px 10px;
  background-color: white;
}
button {
    padding: 5px;
}
button:hover {
  background-color: black;
  color: white;
}
#result {
  color: darkblue;
}