#bb-contenedor {
    max-width: 800px;
    margin: 0 auto;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

#bb-menu-libros {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
}

.bb-libro-btn {
    padding: 12px 20px;
    background: #2c3e50;
    color: #fff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 15px;
    transition: background 0.3s;
}

.bb-libro-btn:hover {
    background: #34495e;
}

.bb-libro-btn.activo {
    background: #e74c3c;
}

#bb-area-preguntas {
    background: #fff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.bb-pregunta {
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 1px solid #eee;
}

.bb-pregunta h3 {
    font-size: 18px;
    margin-bottom: 12px;
    color: #2c3e50;
}

.bb-opcion {
    display: block;
    width: 100%;
    text-align: left;
    padding: 10px 15px;
    margin: 6px 0;
    background: #f8f9fa;
    border: 1px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    font-size: 15px;
    transition: background 0.2s, color 0.2s;
}

.bb-opcion:hover {
    background: #e9ecef;
}

/* NUEVO: Estilo para la opción seleccionada antes de calificar (Azul oscuro y texto blanco) */
.bb-opcion.seleccionada-usuario {
    background: #1b4f72 !important;
    color: #ffffff !important;
    border-color: #154360 !important;
}

.bb-opcion.correcta {
    background: #d4edda !important;
    border-color: #28a745 !important;
    color: #155724 !important;
}

.bb-opcion.incorrecta {
    background: #f8d7da !important;
    border-color: #dc3545 !important;
    color: #721c24 !important;
}

.bb-explicacion {
    margin-top: 10px;
    padding: 10px;
    background: #fff3cd;
    border-left: 4px solid #ffc107;
    font-style: italic;
    color: #856404;
}