body {
      font-family: Arial, sans-serif;
      text-align: center;
      background-color: black;
      color: #03ff00;
    }

    header img {
      width: 55%;
      height: auto;
    }

    form {
      margin: 20px auto;
      padding: 20px;
      border: 2px solid #00f7ff;
      border-radius: 10px;
      width: 90%;
      max-width: 600px;
      background-color: #000;
    }

    label {
      display: block;
      margin-top: 10px;
      font-weight: bold;
    }

    input, select, button {
      width: 90%;
      padding: 10px;
      margin: 10px auto;
      border-radius: 5px;
      border: 1px solid #03ff00;
      background-color: #111;
      color: #03ff00;
    }

    button {
      background-color: #0306f1;
      color: white;
      cursor: pointer;
    }

    button:hover {
      background-color: #00f7ff;
      color: black;
    }

    .titulo {
      color:#0306f1;
      margin-top: 30px;
    }

    #cantidadAlumnos::placeholder {
    color: #03ff00;
    }
    #cantidadAlumnos:focus::placeholder {
    color: transparent;
    /* o: opacity: 0; */
    }

    #signature {
      background-color: #000;
      border: 4px solid #0306f1;
      border-radius: 10px;
      touch-action: none;
    }
    
    #clearBtn {
      background-color: #0306f1;
      color: white;
      cursor: pointer;
    }

    #clearBtn:hover {
      background-color: #00f7ff;
      color: black;
    }
    
    #clearBtn:disabled {
      background-color: #888;
      cursor: not-allowed;
    }

    table {
      margin: 30px auto;
      border-collapse: separate;
      border-spacing: 0;
      width: 95%;
      background-color: #000;
      box-shadow: 0 0 10px #00f7ff;
      border-radius: 10px;
      overflow: hidden;
      color: #03ff00;
    }

    th {
      background-color: #0306f1;
      color: white;
      padding: 12px;
      font-size: 16px;
      border-bottom: 2px solid #00f7ff;
    }

    td {
      padding: 10px;
      border-bottom: 1px solid #00f7ff;
      font-size: 15px;
    }

    tr:nth-child(even) {
      background-color: #111;
    }

    tr:hover {
      background-color: #222;
    }

    .redes {
      display: flex;
      justify-content: space-around;
      margin: 2% 5%;
      color: #03ff00;
      flex-wrap: wrap;
    }
    
    @keyframes fadeIn {
      0% { opacity: 0.3; }
      100% { opacity: 1; }
    }

    .rectanguloGrande {
      height: 2cm;
      background-color: #0306f1;
    }

    .rectanguloChico {
      height: 0.5cm;
      background-color: #03ff00;
    }

    #fechaHora {
      text-align: right;
      color: #03ff00;
      font-size: 1.1vw;
      font-weight: bold;
      margin: 1% 5%;
      animation: fadeIn 1.5s ease-in-out infinite alternate;
    }
    
    #grafico {
      display: block;
      margin: 30px auto 0 auto;
      max-width: 800px;
      width: 100%;
      height: 350px;
    }