body {
    text-align: center;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}


.row {
    display: table;
    clear: both;
    margin-left: auto;
    margin-right: auto;
}

.col {
    float: left;
    width: auto;
}

.cell {
    height: 50px;
    width: 50px;
    border-style: solid;
    border-width: 2px;
}