.stars, .twinkling, .clouds {
          position: absolute;
          display: block;
          top: 0;
          bottom: 0;
          left: 0;
          right: 0;
          width: 100%;
          height: 100%;
        }
        
        .stars {
          z-index: 0;
          background: #000 url("https://i.imgur.com/YKY28eT.png") repeat top center;
        }
        
        .twinkling {
          z-index: 1;
          background: transparent url("https://i.imgur.com/XYMF4ca.png") repeat top center;
          animation: move-twink-back 200s linear infinite;
        }
        
        .clouds {
          z-index: 2;
          background: transparent url("https://i.imgur.com/mHbScrQ.png") repeat top center;
          animation: move-clouds-back 200s linear infinite;
        }
        
        @keyframes move-twink-back {
          from {
            background-position: 0 0;
          }
          to {
            background-position: -10000px 5000px;
          }
        }
        @keyframes move-clouds-back {
          from {
            background-position: 0 0;
          }
          to {
            background-position: 10000px 0;
          }
        }