WordPress: Adding last modified date to Twenty Seventeen

How to add Post’s last modified date to the Twenty Seventeen theme.

Step 1.) Add custom style for text color
/wp-content/themes/twentyseventeen/style.css

/* Change to fit your needs */
.entry-date.published {
    color: #e1e1e1;
}
.modified-date {
    color: #9ecbff;
    margin-left: 8px;
    font-style: italic;
}

/* Add a subtle separator */
.date-separator {
    margin: 0 5px;
    color: #666;
}


Step 2.) Modify function twentyseventeen_time_link()
/wp-content/themes/twentyseventeen/inc/template-tags.php

if ( ! function_exists( 'twentyseventeen_time_link' ) ) :

function twentyseventeen_time_link() {
    $modified_time = get_the_modified_time('U');
    $posted_time = get_the_time('U');
    
    if ($modified_time > $posted_time) {
        // Format for published + modified date with better spacing and structure
        $time_string = sprintf(
            '<time class="entry-date published">%1$s</time><span class="modified-date">Updated: %2$s</span>',
            get_the_date(),
            get_the_modified_date()
        );
    } else {
        // Format for published date only
        $time_string = sprintf(
            '<time class="entry-date published">%1$s</time>',
            get_the_date()
        );
    }

    // Wrap the time string in a link, and preface it with 'Posted on'.
    return sprintf(
        '<span class="screen-reader-text">%1$s</span><a href="%2$s" rel="bookmark">%3$s</a>',
        _x('Posted on', 'post date', 'twentyseventeen'),
        esc_url(get_permalink()),
        $time_string
    );
}
endif;