I use this in my elinks hooks.pl to indent hn comments.

    use strict;
    use warnings;
    
    use Encode;
    use Mojo::DOM;

    sub pre_format_html_hook {
        my $url = shift;
        my $html = Mojo::DOM->new(decode_utf8(shift));
    
        if ($url =~ 'news\.ycombinator\.com') {
            $html->find('img[src="s.gif"]')->each(sub { my $e = shift;
                                                        my $w = $e->attr('width');
                                                        my $ns = ' ' x ( $w / 10 );
                                                        $e->replace($ns); });
    }

    return $html;
}