body {
    font-family: sans-serif;
    text-align: center;
    margin-top: 50px;
  }
  h1 {
    margin-bottom: 20px;
  }
  .board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-template-rows: repeat(3, 100px);
    gap: 5px;
    justify-content: center;
    margin-bottom: 20px;
  }
  .cell {
    background: #f0f0f0;
    font-size: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border: 2px solid #333;
  }
  .cell:hover {
    background: #e0e0e0;
  }
  #message {
    font-size: 1.2rem;
    margin-bottom: 10px;
  }
  button {
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
  }