How to add social icons to woocommerce emails?

<?php

if ( ! function_exists( 'de_woo_email_social_icons' ) ) {
    function de_woo_email_social_icons( $icons ) {
        echo '<ul class="de-social-icons">
        <li><a href="#" target="_blank"><i class="fa fa-facebook" aria-hidden="true"></i></a></li>
        <li><a href="#" target="_blank"><i class="fa fa-twitter" aria-hidden="true"></i></a></li>
        <li><a href="#" target="_blank"><i class="fa fa-linkedin" aria-hidden="true"></i></a></li>
        <li><a href="#" target="_blank"><i class="fa fa-instagram" aria-hidden="true"></i></a></li>
        </ul>
        <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
        <style>
            .de-social-icons {
                list-style: none;
                display: flex;
                align-items: center;
                justify-content: center;
                padding-left: 10px;
            }
            .de-social-icons li:not(last-child) {
                margin-right: 10px;
            }            
            .de-social-icons li a {
                background: #939597;
                padding: 5px 2px;
                border-radius: 50%;
                color: #ffffff !important;
            }            
            .de-social-icons .fa {
                width: 20px;
                height: 20px;
            }
        </style>';
        return $icons;
    }
    add_action( 'woocommerce_email_footer_text', 'de_woo_email_social_icons' );
}