body {
      margin: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial;
      background-color: #f9f9f9;
    }

    .contenitore-centrato {
      text-align: center;
      padding: 30px 20px;
    }

    .logo {
      max-width: 100%;
      height: auto;
      margin-bottom: 20px;
    }

    h1 {
      font-size: 24px;
      margin-bottom: 10px;
      color: #800000;
    }

    #utente {
      font-size: 18px;
      margin-bottom: 20px;
      color: #333;
      font-weight: bold;
    }

    .g_id_signin {
      display: inline-block;
      margin-bottom: 30px;
    }

    #presenzeForm {
      display: none;
      margin-top: 20px;
    }

    .pulsanti-container {
      display: flex;
      justify-content: center;
      gap: 20px;
      margin-top: 20px;
    }

    .pulsante-sapienza {
      background-color: #800000;
      color: white;
      border: none;
      border-radius: 8px;
      width: 120px;
      height: 120px;
      font-size: 16px;
      font-weight: bold;
      text-transform: uppercase;
      text-align: center;
      padding: 10px;
      box-shadow: 0 4px 8px rgba(0,0,0,0.2);
      cursor: pointer;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
    }

    /* Modale stile smartphone */
    #modal {
      display: none;
      position: fixed;
      z-index: 9999;
      left: 0; top: 0;
      width: 100%; height: 100%;
      background-color: rgba(0,0,0,0.4);
      backdrop-filter: blur(4px);
    }

    #modal-content {
      background-color: #fff;
      margin: 40% auto;
      padding: 20px;
      border-radius: 12px;
      width: 80%;
      max-width: 320px;
      text-align: center;
      box-shadow: 0 4px 12px rgba(0,0,0,0.2);
      font-size: 16px;
    }

    #modal-content p {
      margin: 10px 0;
    }

    #modal button {
      background-color: #007aff;
      color: #fff;
      padding: 10px 20px;
      border-radius: 8px;
      font-size: 16px;
      border: none;
    }