body {
    font-family: sans-serif;
    background: #f4f4f4;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
  }
  
  main {
    background: white;
    padding: 2rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 90%;
    max-width: 400px;
  }
  
  input[type="text"] {
    width: 100%;
    padding: 0.5rem;
    font-size: 1rem;
    margin-bottom: 1rem;
    border-radius: 8px;
    border: 1px solid #ccc;
  }
  
  button {
    padding: 0.5rem 1rem;
    margin: 0.5rem;
    border: none;
    background-color: #007bff;
    color: white;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
  }
  
  button:hover {
    background-color: #0056b3;
  }
  
  #qrcode {
    margin: 1rem auto;
  }
  
  .hidden {
    display: none;
  }
  footer {
    margin-top: 2rem;
    font-size: 0.8rem;
    color: #666;
    text-align: center;
  }
  
  footer a {
    color: #666;
    text-decoration: underline;
  }