.dino {
    position: absolute;
    width: 60px;
    height: 60px;
    background-image: url(image/t-rex.png);
    bottom: 0px;
  }
  
  .obstacle {
    position: absolute;
    width: 60px;
    height: 60px;
    background-image: url(image/cacti.png);
    bottom: 0px;
  }
  
  @keyframes slideright {
    from {
        background-position: 70000%;
    }
    to {
        background-position: 0%;
    }
  }
  
  @-webkit-keyframes slideright {
    from {
        background-position: 70000%;
    }
    to {
        background-position: 0%;
    }
  }
  
  #desert {
    position: absolute;
    bottom: 0px;
    background-image: url('image/t-rex-background.png');
    background-repeat: repeat-x;
    animation: slideright 600s infinite linear;
    -webkit-animation: slideright 600s infinite linear;
    width: 100%;
    height: 200px;
  }