add_filter("the_content", "learndash_course_grid_css");
function learndash_course_grid_css($content) {
    if(strpos($content, "[ld_course_list") === false)
        return $content;

    wp_enqueue_style( 'learndash_course_grid_css', plugins_url( 'style.css', __FILE__ ) );
    wp_enqueue_script( 'learndash_course_grid_js', plugins_url( 'script.js', __FILE__ ), array('jquery') );
    wp_enqueue_style( 'ld-cga-bootstrap', plugins_url( 'bootstrap.min.css', __FILE__ ) );

    return str_replace("[ld_course_list", "<div id='ld_course_list'>[ld_course_list", $content);
}