.container {
  max-width: 600px;
  margin: 50px auto;
  text-align: center;
}

#board {
  display: grid;
  grid-template-columns: repeat(8, 50px);
  border: 2px solid black;
}

.cell {
  width: 50px;
  height: 50px;
  line-height: 50px;
  text-align: center;
  border: 1px solid black;
  background-color: #eee;
  cursor: pointer;
}

.cell.black {
  background-color: #777;
}