File: htdocs/themes/xbootstrap5/modules/system/system_comments_nest.tpl

<div class="xoops-comment-body">
    <{section name=i loop=$comments}>
        <div class="row">
            <div class="col-2 col-md-2"><strong><{$lang_poster}></strong></div>
            <div class="col-10 col-md-10"><strong><{$lang_thread}></strong></div>
        </div>
        <{include file="db:system_comment.tpl" comment=$comments[i]}>
        <!-- start comment replies -->
        <{foreach item=reply from=$comments[i].replies|default:null}>
            <{assign var="indent" value=$reply.prefix/25}>
            <{assign var="fullcolwidth" value="12"}>

            <{if $indent>3}>
                <{assign var="indent" value="3"}>
            <{/if}>
            <{assign var="replyspace" value=$fullcolwidth-$indent}>
            <div class="row">
                <div class="col-md-offset-<{$indent}> col-md-<{$replyspace}> col-offset-<{$indent}> col-<{$replyspace}>">
                    <{include file="db:system_comment.tpl" comment=$reply}>
                </div>
            </div>
        <{/foreach}>
    <{/section}>
    <{if isset($commentform)}>
        <div class="aligncenter">
            <button class="btn-comment btn btn-primary btn-md" data-bs-toggle="modal" data-bs-target="#comments-form">
                <span class="fa-solid fa-comment"></span> Add Comment
            </button>
        </div>
        <!-- Modal -->
        <div class="modal fade" id="comments-form" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
            <div class="modal-dialog comments-modal">
                <div class="modal-content">
                    <div class="modal-body">
                        <div class="xoops-comment-form">
                            <{$commentform}>
                        </div>
                    </div>
                    <div class="modal-footer">
                        <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">&times;</button>
                    </div>
                </div><!-- /.modal-content -->
            </div><!-- /.modal-dialog -->
        </div>
        <!-- /.modal -->
    <{/if}>
</div>