body {
    font-family: 'Poppins', sans-serif;
    background-color: #f9fafb;
    color: #1f2937;
    margin: 0;
    padding: 0;
}

.contenedor {
    max-width: 800px;
    margin: 50px auto;
    padding: 20px;
}

.card-detalle {
    background: #ffffff;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.card-detalle h1 {
    font-size: 26px;
    margin-bottom: 10px;
}

.card-detalle .autor {
    font-size: 16px;
    color: #6b7280;
    margin-bottom: 20px;
}

.imagen-libro img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: 20px;
}

.descripcion h3 {
    margin-bottom: 10px;
    font-size: 20px;
}

.descripcion p {
    font-size: 15px;
    line-height: 1.6;
    color: #374151;
}

.btn-volver {
    display: inline-block;
    margin-top: 25px;
    text-decoration: none;
    padding: 10px 18px;
    background-color: #3b82f6;
    color: #ffffff;
    border-radius: 6px;
    transition: background 0.3s;
}

.btn-volver:hover {
    background-color: #2563eb;
}