html, body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
  background: linear-gradient(to bottom, black, rgb(0, 0, 255));
}

h1 {
  color: whitesmoke;
  width: 100%;
  margin: 0 auto;
}

#d_title {
  padding-top: 300px;
  text-align: center;
}