table {
    color: #fff;                                        
    text-align: center;
    border-collapse: collapse;
    font: normal 3em Arial, Helvetica,sans-serif;
}

tr {
    height: 16.02vh;                                /* 16.02vh is approximately 100px */
    background-color: #4e494d;
}

td {
    width: 25vw;                                    /* 25vw is approximately 200px */
    border: 1px solid #4e494d;                    
}

#inputBox {                                         /*We use # and not . because it is an ID and not a class*/
    width: 100%;                                    
    font-size: 2em;
    color: #fff;
    border: 0px;
    text-align: right;
    background-color: #4e494d;
}

.digitBtn {
    background-color: #807e80;
}

.operatorBtn {
    background-color: #ff9e06;
}

.ACBtn {
    background-color: #656165;
}