public function color_scheme( WP_Customize_Manager $wp_customize ) {

		if ( count( $this->color_schemes ) < 2 ) {

			return;

		}

		$wp_customize->add_setting(
			'color_scheme',
			array(
				'default'           => 'default',
				'sanitize_callback' => array( $this, 'sanitize_color_scheme' ),
				'transport'         => 'postMessage',
			)
		);

		$choices = array_combine(
			array_keys( $this->color_schemes ),
			wp_list_pluck( $this->color_schemes, 'label' )
		);

		$wp_customize->add_control(
			'color_scheme',
			array(
				'label'    => esc_html__( 'Base Color Scheme', 'rock' ),
				'section'  => 'colors-scheme',
				'type'     => 'select',
				'choices'  => $choices,
				'priority' => 1,
			)
		);

	}