body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    background: #282c34;
    color: #fff;
  }
  
  h1 {
    margin-bottom: 20px;
  }
  
  .game-container {
    display: grid;
    grid-template-columns: repeat(4, 80px);
    gap: 15px;
  }
  
  .card {
    width: 80px;
    height: 80px;
    background: #444;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    cursor: pointer;
    border-radius: 10px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.5s;
  }
  
  .card.flipped {
    transform: rotateY(180deg);
  }
  
  .card .front,
  .card .back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .card .front {
    background: #61dafb;
    transform: rotateY(180deg);
  }
  
  .card .back {
    background: #444;
  }
  
  button {
    margin-top: 20px;
    padding: 10px 20px;
    background: #61dafb;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    cursor: pointer;
  }
  
  button:hover {
    background: #21a1f1;
  }