#tahtaCerceve {
    width: 240px;
    height: 240px;
    border: 3px solid black;
}

.kareBeyaz {
    width: 30px;
    height: 30px;
    background-color: white;
    float: left;
}

.kareSiyah {
    width: 30px;
    height: 30px;
    background-color: black;
    float: left;
}