body {
    background-color: #ffffff;
  }
  h4 {
    color: #000000;
    font-weight: bold;
  }  
  h1 {
    color: #000000;
    margin-left: 20px;
  }
  a {
    color: #000000;
  }
  .code {
    background-color: #dddddd;
    border-style: dotted;      
  }