.display{
    border: 10px solid gray;
    height: 200px;
    width: 99%;
    background-color: #e6e6e6 ;
    margin:auto;
    font-size: 30px;
}
.keyboard{
    background-color: #993300;
}
.center{
    margin: auto;
    width: 50%;
    border: 5px black;
    padding: 10px;
}