function mytheme_register_meta_boxes( $meta_boxes ){
    $prefix = 'mytheme_';

    // Page builder
    $meta_boxes[] = array(
        'id'       => $prefix . 'page-builder',
        'title'    => esc_html__( 'Page Builder', 'mytheme' ),
        'pages'    => array( 'page' ),
        'context'  => 'normal',
        'priority' => 'high',
        'show'     => array(
            'template'    => array( 'page-builder.php' ),
        ),

        'fields' => array(
            array(
                'id'            => $prefix . 'pb-section',
                'type'          => 'group',
                'collapsible'   => true,
                'clone'         => true,
                'max_clone'     => 100,
                'group_title'   => array(
                    'field'     => $prefix . 'pb-section-select',
                ),
                'sort_clone'    => true,
                'save_state'    => true,
                // List of sub-fields
                'fields' => array(
                    array(
                        'name'          => esc_html__('Section', 'mytheme'),
                        'id'            => $prefix . 'pb-section-select',
                        'type'          => 'select',
                        'placeholder'   => esc_html__( 'Select a section', 'mytheme' ),
                        'options'       => array(
                            'ft-slider' => esc_html__( 'Featured Slider', 'mytheme' ),
                            'with-sidebar' => esc_html__( 'With Sidebar Section', 'mytheme' ),
                        ),
                    ),
                    // #Featured Slider fields.
                    array(
                        'id'            => $prefix . 'pb-ft-slider-configs',
                        'type'          => 'group',
                        'group_title'   => false,
                        'visible'       => array( $prefix . 'pb-section-select', '=', 'ft-slider' ),
                        // List of sub-fields
                        'fields' => array(
                            array(
                                'id'       => $prefix . 'pb-ft-slider-post-source',
                                'name'     => esc_html__( 'Posts Source', 'mytheme' ),
                                'type'     => 'button_group',
                                'options'  => array(
                                    'latest'        => esc_html__( 'Latest', 'mytheme' ),
                                    'by-cats'       => esc_html__( 'By categories', 'mytheme' ),
                                    'by-tags'       => esc_html__( 'By tags', 'mytheme' ),
                                    'manually'      => esc_html__( 'Select manually', 'mytheme' ),
                                ),
                                'inline'   => true,
                                'std'      => 'latest',
                            ),
                            array(
                                'id'            => $prefix . 'pb-ft-slider-cats',
                                'name'          => esc_html__( 'Categories Select', 'mytheme' ),
                                'placeholder'   => esc_html__( 'Select categories', 'mytheme' ),
                                'type'          => 'taxonomy',
                                'taxonomy'      => 'category',
                                'field_type'    => 'select_advanced',
                                'multiple'      => true,
                                'query_args'    => array(
                                    'hide_empty'    => true,
                                ),
                                'visible'       => array( $prefix . 'pb-ft-slider-post-source', '=', 'by-cats' ),
                            ),
                            array(
                                'id'            => $prefix . 'pb-ft-slider-tags',
                                'name'          => esc_html__( 'Tags Select', 'mytheme' ),
                                'placeholder'   => esc_html__( 'Select tags', 'mytheme' ),
                                'type'          => 'taxonomy',
                                'taxonomy'      => 'post_tag',
                                'field_type'    => 'select_advanced',
                                'multiple'      => true,
                                'query_args'    => array(
                                    'hide_empty'    => true,
                                ),
                                'visible'       => array( $prefix . 'pb-ft-slider-post-source', '=', 'by-tags' ),
                            ),
                            array(
                                'id'            => $prefix . 'pb-ft-slider-posts',
                                'name'          => esc_html__( 'Posts Select', 'mytheme' ),
                                'placeholder'   => esc_html__( 'Select posts', 'mytheme' ),
                                'type'          => 'post',
                                'post_type'     => 'post',
                                'field_type'    => 'select_advanced',
                                'multiple'      => true,
                                'query_args'    => array(
                                    'post_status'    => 'publish',
                                    'posts_per_page' => 100,
                                ),
                                'visible'       => array( $prefix . 'pb-ft-slider-post-source', '=', 'manually' ),
                            ),
                        ),
                    ),
                    // #Content with sidebar section.
                    array(
                        'id'            => $prefix . 'pb-section-main-col',
                        'type'          => 'group',
                        'collapsible'   => true,
                        'clone'         => true,
                        'max_clone'     => 100,
                        'group_title'   => array(
                            'field'     => 'section-main-col-select',
                        ),
                        'sort_clone'    => true,
                        'save_state'    => true,
                        'visible'       => array( 'section-select', '=', 'with-sidebar' ),
                        // List of sub-fields
                        'fields' => array(
                            array(
                                'name'          => esc_html__('Section', 'mytheme'),
                                'id'            => 'section-main-col-select',
                                'type'          => 'select',
                                'placeholder'   => esc_html__( 'Select a layout', 'mytheme' ),
                                'options'       => array(
                                    'posts-listing' => esc_html__( 'Posts Listing', 'mytheme' ),
                                    'slider' => esc_html__( 'Slider', 'mytheme' ),
                                ),
                            ),
                        ),
                    ),
                ),
            ),
        ),
    );

    return $meta_boxes;
}