body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
  }
  
  header, main, footer {
    margin: 10px;
    padding: 10px;
    border: 1px solid #ddd;
  }
  
  .content-table {
    margin: 10px;
    padding: 10px;
    display: inline-block;
    width: 100%;
    box-sizing: border-box;
  }
  
  table {
    width: 100%;
    border-collapse: collapse;
  }
  
  table, th, td {
    border: 1px solid #ddd;
  }
  
  @media screen and (min-width: 600px) {
    main {
      display: flex;
    }
  
    .content-table {
      width: 30%;
    }
  
    .content-table table {
      width: 100%;
    }
  }
  body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
  }
  
  header, main, footer {
    margin: 10px;
    padding: 10px;
    border: 1px solid #ddd;
  }
  
  .main-nav {
    display: flex;
  }
  
  .main-nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
  }
  
  .main-nav li {
    margin-right: 15px;
  }
  
  .main-nav a {
    text-decoration: none;
    color: #333;
  }
  
  .dropdown {
    position: relative;
    display: inline-block;
  }
  
  .dropbtn {
    cursor: pointer;
  }
  
  .dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
  }
  
  .dropdown-content a {
    color: #333;
    padding: 12px 16px;
    display: block;
    text-decoration: none;
  }
  
  .dropdown-content a:hover {
    background-color: #ddd;
  }
  
  .dropdown:hover .dropdown-content {
    display: block;
  }
  
  @media screen and (max-width: 600px) {
    .main-nav {
      flex-direction: column;
    }
  
    .main-nav li {
      margin-right: 0;
      margin-bottom: 5px;
    }
  
    .dropdown {
      display: block;
    }
  
    .dropdown-content {
      position: static;
      display: none;
      overflow: hidden;
    }
  
    .dropdown:hover .dropdown-content {
      display: none;
    }
  }