.board {
  width: 348px;
  height: 348px;
  display: flex;
  flex-wrap: wrap;
  background-color: grey;
}


div {
  height: 30px;
  width: 30px;
  border-color: white;
  border-style: solid;
}

#titlu {
  font-size: 50px;
}

.checked {
  background-color: lightblue;
}