html {
  background-image: url('/background_black.jpg');
  background-color: black;
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  
  font-family: serif;
  color: white;
  }
  
body {
  background-color: rgba(0, 0, 0, 0.5);
  margin: 100px;
  padding: 30px;
  
}