body {
  text-align: center;
  background-color: #efd81d;
}
h1 {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  margin-top: auto;
}
.d {
  height: 600px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.key {
  font-size: 15rem;
}