.contenedor-lectura {
        padding: 20px;
        max-width: 1000px;
        margin: 0 auto;
    }

    .barra-regreso {
        display: flex;
        align-items: center;
        gap: 15px;
        margin-bottom: 30px;
        padding-bottom: 15px;
        border-bottom: 2px solid #ddd;
    }

    .btn-regreso {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        width: 40px;
        height: 40px;
        background-color: #007bff;
        color: white;
        border-radius: 50%;
        text-decoration: none;
        font-size: 18px;
        transition: background-color 0.3s;
    }

    .btn-regreso:hover {
        background-color: #0056b3;
    }

    .titulo-libro {
        font-size: 24px;
        font-weight: bold;
        color: #333;
    }

    .info-libro {
        display: flex;
        gap: 30px;
        margin-bottom: 30px;
        padding: 20px;
        background-color: #f9f9f9;
        border-radius: 8px;
    }

    .portada-lectura {
        width: 150px;
        height: 200px;
        object-fit: cover;
        border-radius: 8px;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    }

    .detalles-libro {
        flex: 1;
        display: flex;
        flex-direction: column;
        justify-content: center;
    }

    .detalles-libro h2 {
        margin: 0 0 15px 0;
        color: #333;
    }

    .detalles-libro p {
        margin: 8px 0;
        color: #666;
        font-size: 16px;
    }

    .visor-pdf,
    .visor-audio {
        margin: 30px 0;
        border-radius: 8px;
        overflow: hidden;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    }

    .visor-pdf iframe {
        width: 100%;
        height: 600px;
        border: none;
    }

    .visor-audio {
        padding: 20px;
        background-color: #f9f9f9;
    }

    .visor-audio h3 {
        margin-top: 0;
        margin-bottom: 20px;
        color: #333;
        font-size: 18px;
    }

    .visor-audio iframe {
        width: 100%;
        border-radius: 8px;
    }

    .botones-lectura {
        display: flex;
        gap: 15px;
        justify-content: center;
        margin-top: 30px;
        flex-wrap: wrap;
    }

    .btn {
        padding: 10px 20px;
        border: none;
        border-radius: 5px;
        cursor: pointer;
        font-size: 16px;
        text-decoration: none;
        display: inline-flex;
        align-items: center;
        gap: 8px;
        transition: all 0.3s;
    }

    .btn-descargar {
        background-color: #28a745;
        color: white;
    }

    .btn-descargar:hover {
        background-color: #218838;
    }

    .btn-volver {
        background-color: #6c757d;
        color: white;
    }

    .btn-volver:hover {
        background-color: #5a6268;
    }

    @media (max-width: 768px) {
        .info-libro {
            flex-direction: column;
            align-items: center;
        }

        .portada-lectura {
            width: 120px;
            height: 160px;
        }

        .visor-pdf iframe {
            height: 400px;
        }

        .barra-regreso {
            flex-wrap: wrap;
        }

        .titulo-libro {
            font-size: 18px;
        }
    }