body{

}

table{
    border: 8px double black;
    border-spacing: 0;
    font-size: 1.4em;
}


td{
    background-color: white;
    color: black;
    height: 40px;
    width: 40px;
    text-align: center;
    vertical-align: middle;
}

tr:nth-child(even) td:nth-child(odd){
    background-color: black;
    color: white;
}

tr:nth-child(odd) td:nth-child(even){
    background-color: black;
    color: white;
}