body {
    font-family: 'Segoe UI', sans-serif;
    background: #f9f9f9;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
  }
  
  .container {
    text-align: center;
  }
  
  h1 {
    margin-bottom: 20px;
    color: #333;
  }
  
  .board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-gap: 5px;
    margin: 0 auto;
  }
  
  .cell {
    width: 100px;
    height: 100px;
    background-color: #fff;
    border: 2px solid #333;
    font-size: 2.5rem;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
  }
  
  .cell.X {
    color: #007bff;
  }
  
  .cell.O {
    color: #ff4136;
  }
  
  button {
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
    
  }
  
  #message {
    margin-top: 15px;
    font-weight: bold;
    color: #222;
  }