html, body {
    height: 100%;
    margin: 0;
    font-family: Verdana, sans-serif;
    }
table {
    width: 100%;
    height: 100%;
    border-collapse: collapse;
    table-layout: fixed;
    }
tr { height: 20%; }

td {
    background-color: black;
    color: white;
    border:3px solid white;
    text-align:center;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 6vw;
    word-wrap: break-word;
    overflow-wrap: break-word;
    hyphens: auto; 
    }

td.light {
    background-color: white;
    color:black;
    }