@media (max-width:800px) {
    body{
        margin-left:20%;
        font-family: Arial, Helvetica, sans-serif;
        text-align: center;
        font-size: 32px; 
        color:green; 
        font-weight: bold; 
        width:550px;
        margin-left:20%;
        border:5px solid #CCC;
        border-radius: 15px
    }
}