<style>
    body {
      font-family: Arial, sans-serif;
      line-height: 1.6;
      margin: 20px;
      background-color: #f4f4f4;
    }
    header {
      background: #333;
      color: #fff;
      padding: 10px 0;
      text-align: center;
    }
    nav ul {
      list-style-type: none;
      margin: 0;
      padding: 0;
      text-align: center;
    }
    nav ul li {
      display: inline;
      margin-right: 10px;
    }
    nav ul li a {
      color: #333;
      text-decoration: none;
    }
    main {
      background: #fff;
      padding: 20px;
      border-radius: 5px;
      box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    }
    article h2 {
      color: #333;
    }
    footer {
      background: #333;
      color: #fff;
      padding: 10px 0;
      text-align: center;
      position: fixed;
      bottom: 0;
      width: 100%;
    }
  </style>