WordPress Theme install and customize Widgets format

    /* Install Theme */
    if(!function_exists('nitron_setup')){
        function nitron_setup(){
            add_theme_support("title-tag");
            add_theme_support('automatic-feed-links');
            add_theme_support('post-thumbnails');
            add_image_size('thumbnail_250_250', '250', '250', TRUE);
            add_theme_support('thumbnail_250_250');
            register_nav_menus(array('header'=>esc_html__('Header','nitron')));
        }
    }
    add_action('after_setup_theme','nitron_setup');

    /* Register Sidebar & define the Widget HTML format */
    if (!function_exists('nitron_sidebars')){
        function nitron_sidebars(){
            register_sidebar(array(
                'name' => esc_html__('aSidebar', 'nitron'),
                'id' => 'asidebar',
                'description' => esc_html__('Aggiungi/Togli i Widget che vuoi.', 'nitron'),
                'before_widget' => '<div id="%1$s" class="sidebox widget %2$s">',
                'after_widget' => '</div><!-- .widget-content --></div><!-- .sidebox -->',
                'before_title' => '<h4 class="toggle">',
                'after_title' => '<img class="col-icon" src="'.get_template_directory_uri().'/img/Maximize-Window.svg" /></h4><div class="widget-toggle-content">'
            ));
        }
    }
    add_action('widgets_init', 'nitron_sidebars');