.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 10px;
  width: 300px;
  margin-bottom: 10px;
}

.cell {
  width: 100px;
  height: 100px;
  background-color: lightgray;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 40px;
  cursor: pointer;
}

button {
  font-size: 20px;
}