.btn {
    background: #d9c334;
    background-image: -webkit-linear-gradient(top, #d9c334, #87b82b);
    background-image: -moz-linear-gradient(top, #d9c334, #87b82b);
    background-image: -ms-linear-gradient(top, #d9c334, #87b82b);
    background-image: -o-linear-gradient(top, #d9c334, #87b82b);
    background-image: linear-gradient(to bottom, #d9c334, #87b82b);
    -webkit-border-radius: 6;
    -moz-border-radius: 6;
    border-radius: 6px;
    -webkit-box-shadow: 5px 5px 7px #666666;
    -moz-box-shadow: 5px 5px 7px #666666;
    box-shadow: 5px 5px 7px #666666;
    font-family: Arial;
    color: #ffffff;
    font-size: 25px;
    padding: 12px;
    text-decoration: none;
  }
  
  .btn:hover {
    background: #dae2e6;
    background-image: -webkit-linear-gradient(top, #dae2e6, #3498db);
    background-image: -moz-linear-gradient(top, #dae2e6, #3498db);
    background-image: -ms-linear-gradient(top, #dae2e6, #3498db);
    background-image: -o-linear-gradient(top, #dae2e6, #3498db);
    background-image: linear-gradient(to bottom, #dae2e6, #3498db);
    text-decoration: none;
  }
  #one:hover{
    offset: 5px 20px;
    border: 2px solid white;
    box-shadow: 5px 5px 10px 5px;
  }
  .ball {
    position: absolute;
    border-radius: 100%;
    opacity: 0.7;
  }
  .img{
    width: 500px;
    height: 500px;
    background-image: url("c++.jpg");
  }