WordPress Customizer Help with FontAwesome Icon

Here’s the scenario – I want to select fontawesome icons from the dropdown list but it’s not working. For some reason the class inside span is not adding up (I have tried jQuery().append(), CSS) but so far no luck. ANY help would be appreciated.

Code in Page.php file

<div class="features-block-one">
  <div class="icon-one">
   <span class="<?php get_theme_mod('features_one_icon' ,'fa fa-bullseye');?>">  </span>
  </div>
</div>

Code in Customizer file

//block one icon
       $wp_customize->add_setting(
        'features_one_icon',
        array(
            'default' => 'fa-fa box',
            'transport' => 'postMessage',
            'sanitize_callback' => 'sanitize_key',
        )
    );

    $wp_customize->add_control(
        'features_one_icon_control',
         array(
            'label' => __('Select Icon', 'text-domain'),
            'section' => 'features_block',
            'type' => 'select',
            'settings' => 'features_one_icon',
            'choices' => tar_icons() /*With function tar_icons() I'm pulling all the icons from the function */
        )
    );

Code in customizer.js file

wp.customize( 'features_one_icon', function( value ) {
        value.bind( function( to ) {
            $( '.features-block-one .icon-one span' ).css( to  );
          } );
    } );

<span class="<?php echo get_theme_mod('features_one_icon' ,'fa fa-bullseye');?>">  </span>