Aggiungi tutti i Controlli che desideri al Theme Customizer: https://skillsandmore.org/aggiungi-controlli-theme-customizer/

1_functions.php

<?php

//* Aggiungo la pagina d'esempio per i componenti 
include_once( get_stylesheet_directory() . '/inc/theme-customizer/theme-customizer-demo.php' );

2_functions.php

<?php 

/** 
 * Register the breadcrumbs settings and controls. 
 * 
 * @since 2.1.0 
 * 
 * @param WP_Customize_Manager $wp_customize WP_Customize_Manager instance. 
*/ 
private function breadcrumbs( $wp_customize ) { 
	$wp_customize->add_section( 
		'genesis_breadcrumbs', 
		array( 
			'title' => __( 'Breadcrumbs', 'genesis' ), 
			'priority' => '158.82', 
		) 
	); 

	$settings = array( ... ); 
	$priority = 1; 

	foreach ( $settings as $setting => $label ) { 
		$wp_customize->add_setting( ... ); 
		$wp_customize->add_control( ... ); 
		$priority++; 
	} 
}

3_functions.php

<?php 

function sam_breadcrumb_edit( $wp_customize ){ 
	require_once dirname(__FILE__) . '/inc/theme-customizer/select/google-font-dropdown-custom-control.php'; 

	$wp_customize->add_setting( 
		'google_font_setting', 
		array( 'default' => '', )
	); 

	$wp_customize->add_control( 
		new Google_Font_Dropdown_Custom_Control( 
			$wp_customize, 
			'google_font_setting', 
			array( 
				'label' => 'Seleziona il font da Google', 
				'section' => 'genesis_breadcrumbs', 
				'settings' => 'google_font_setting', 
				'type' => 'select', 
				'priority' => 1 
			)
		)
	); 
}

4_functions.php

<?php

function sam_inserisco_css() { 
	?> 
	<style type="text/css"> 
		.breadcrumb { 
			font-family: <?php echo get_theme_mod('google_font_setting', 'Arial'); ?>; 
		} 
	</style> 
	<?php 
} 

add_action( 'wp_head', 'sam_inserisco_css');