body {
  background: #f5f5f5;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  font-family: Arial, sans-serif;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 20px;
}

.cell {
  background: #e0e5ec;
  border-radius: 20px;
  box-shadow: 9px 9px 16px #a3b1c6, -9px -9px 16px #ffffff;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 2rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cell.x::after {
  content: "X";
  color: #555;
}

.cell.o::after {
  content: "O";
  color: #555;
}

.cell:hover {
  transform: scale(1.05);
  box-shadow: 9px 9px 16px #a3b1c6, -9px -9px 16px #ffffff;
}

.winning-message {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #e0e5ec;
  padding: 40px;
  border-radius: 20px;
  box-shadow: 9px 9px 16px #a3b1c6, -9px -9px 16px #ffffff;
  display: none;
  flex-direction: column;
  align-items: center;
}

.winning-message.show {
  display: flex;
}

.winning-message button {
  margin-top: 20px;
  background: #e0e5ec;
  border: none;
  padding: 10px 20px;
  border-radius: 10px;
  box-shadow: 9px 9px 16px #a3b1c6, -9px -9px 16px #ffffff;
  cursor: pointer;
}

@media (max-width: 500px) {
  .board {
    grid-template-columns: repeat(3, 70px);
    grid-template-rows: repeat(3, 70px);
    gap: 15px;
  }

  .cell {
    font-size: 1.5rem;
  }
}