* { margin: 0; padding: 0; box-sizing: border-box; }

  body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #b71c1c 0%, #d32f2f 100%);
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
  }

  .login-box {
    background: white;
    color: #333;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    text-align: center;
    width: 100%;
    max-width: 380px;
  }

  .login-box img {
    width: 200px;
    margin-bottom: 15px;
  }

  .login-box h2 {
    font-size: 1.3rem;
    font-weight: bold;
    color: #b71c1c;
    margin: 5px 0;
  }

  .login-box h3 {
    font-size: 1rem;
    color: #666;
    margin-bottom: 20px;
  }

  .input-group {
    margin-bottom: 15px;
    text-align: left;
  }

  .input-group label {
    display: block;
    font-size: 0.9rem;
    font-weight: bold;
    color: #333;
    margin-bottom: 5px;
  }

  input[type="text"], input[type="password"] {
    width: 100%;
    padding: 12px;
    border-radius: 6px;
    border: 2px solid #e0e0e0;
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
  }

  input[type="text"]:focus, input[type="password"]:focus {
    outline: none;
    border-color: #b71c1c;
    box-shadow: 0 0 0 3px rgba(183,28,28,0.12);
  }

  /* ✅ evita rosso subito all'apertura: solo dopo che l'utente ha scritto */
  input:invalid:not(:placeholder-shown) {
    border-color: #dc3545;
  }

  .checkbox-label {
    display: flex;
    align-items: center;
    font-size: 0.9rem;
    justify-content: center;
    margin: 15px 0;
    color: #666;
  }

  .checkbox-label input {
    margin-right: 8px;
    width: auto;
  }

  button {
    width: 100%;
    padding: 14px;
    margin-top: 10px;
    background: #b71c1c;
    color: white;
    border: none;
    border-radius: 6px;
    font-weight: bold;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
  }

  button:hover {
    background: #9f1b1b;
    transform: translateY(-1px);
  }

  button:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
  }

  #errore {
    color: #dc3545;
    background: #f8d7da;
    border: 1px solid #f5c6cb;
    padding: 10px;
    border-radius: 6px;
    margin-top: 15px;
    font-size: 0.9rem;
    display: none;
  }

  #errore.show { display: block; }

  .help-text {
    font-size: 0.85rem;
    color: #999;
    margin-top: 15px;
  }

  .help-text strong { color: #b71c1c; }

  @media (max-width: 480px) {
    .login-box { padding: 30px 20px; }
    .login-box img { width: 160px; }
  }