/* https://www.w3schools.com/howto/howto_js_topnav.asp */
 body{
     margin: 0;
     font-family: Arial;
}
 p{
    max-width: 60em;
}
 .topnav {
     overflow: hidden;
     background-color: #333;
}
 @media print {
     .topnav a {
         visibility: hidden;
         padding: 14px 0;
         text-decoration: none;
         font-size: 17px;
    }
     .topnav a.active {
         visibility: visible;
         color: black;
         background-color: white;
         padding: 10px;
    }
}
 @media not print {
     .topnav a {
         float: left;
         color: #f2f2f2;
         text-align: center;
         padding: 14px 16px;
         text-decoration: none;
         font-size: 17px;
    }
     .topnav a.active {
         background-color: #009622;
         color: white;
    }
}
 .topnav h1 {
     float: left;
     color: #f2f2f2;
     text-align: center;
     padding: 14px 16px;
     text-decoration: none;
     font-size: 30px;
}
 .topnav a:hover {
     background-color: #ddd;
     color: black;
}
 .content {
     padding-left: 16px;
     padding-bottom: 20px;
}
 .shad {
    margin-left: 8em;
    border: 1px solid #ccc;
    width: 288px;
    height: 512px;
    box-shadow: 2px 2px 7px 2px #ddd;
}
 .shad img{
    width: 100%;
}