function acf_style() {

    $feature_icon_style = get_field( 'feature_icon_style', 'options');
?>

    <style>
        .services-2 .icon {
            background-color: <?php echo $feature_icon_style ['feature_icon_background'];?>;
        }
        .services-2 .icon i{
            color: <?php echo $feature_icon_style ['feature_icon_color'];?>;
            font-size: <?php echo $feature_icon_style ['feature_icon_size'];?>;
        }
    </style>

<?php
}

add_action( 'wp_head', 'acf_style' );