body {
       background-image:url(circuit.jpg);
     }
     
     a {
       color:#000;
       font-weight: bold;
     }
     
     a:visited {
       color:#333;
     }
     
     img {
       max-width:100%;
     }
     
     #tut {
       border:2px solid black;
       border-radius:20px;
       background-color:#ffffffcc;
       margin: 20px;
       padding: 10px;
     }

     h1 {
       text-align:center;
     }

     p {
       text-indent: 2em;
     }
     
     textarea {
       width: 800px;
       margin: auto;
       display: block;
     }
     

@media only screen and (max-width: 999px) {

     textarea {
       width: 95%;
     }
     
}