html { 
    margin:0;
    padding:0;
    background-repeat: no-repeat;
    background-position: center;
    background-attachment: fixed;
    -webkit-background-size: cover; /* pour anciens Chrome et Safari */
    background-size: cover; /* version standardisée */
  
  }
  
  body {
      background: none !important;
  }
  
  h3 {
      background:white;
      text-align: center;
      margin-bottom: 2rem;
      padding: 1.5rem 0;
      border-radius: .5rem;
  }
  
  
  .copyright {
      background:white;
      text-align: center;
      margin-bottom: 2rem;
      padding: 1.5rem 0;
      padding-bottom: .5rem;
      border-radius: .5rem;
  }