body 
{
    margin: 0;
    padding: 0;
    background-color: gray;
}

.centered 
{
    margin: auto;
    padding: 20px;
    padding-top: 10px;
    padding-bottom: 40px;
    max-width: 800px;
    //border: 3px solid green;
    background-color: white;    
}