body {
  font-family: Arial, sans-serif;
  text-align: center;
  background-color: black;
  color: white;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 5px;
  background-color: black;
  padding: 10px;
}

.cell {
  width: 100px;
  height: 100px;
  background-color: #222;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  font-weight: bold;
  cursor: pointer;
  color: white;
  border: 2px solid white;
}

.cell.winner {
  background-color: #00aaff;
}

button {
  margin-top: 10px;
  padding: 10px;
  font-size: 16px;
  cursor: pointer;
}