Modify content region

do you mean like a teaser separations like this ond the screen?

for the first page or front page where displayes the teaser of nodes you can use folow css tags

.node-teaser
{
	border-bottom-color: #ddd;
	border-bottom-width: 1px;
	border-bottom-style: solid;
}

an if you want all under the node then you need the node.tpl.php from the modules node to copy to the templates folder in tapestry and change to

<div id="node-<?php print $node->nid; ?>" class="<?php print $classes; ?> clearfix"<?php print $attributes; ?>>

  <?php print $user_picture; ?>

  <?php print render($title_prefix); ?>
  <?php if (!$page): ?>
    <h2<?php print $title_attributes; ?>><a href="<?php print $node_url; ?>"><?php print $title; ?></a></h2>
  <?php endif; ?>
  <?php print render($title_suffix); ?>


  <div class="content"<?php print $content_attributes; ?>>
    <?php
      // We hide the comments and links now so that we can render them later.
      hide($content['comments']);
      hide($content['links']);
      print render($content);
    ?>
  </div>

  <?php if ($display_submitted): ?>
    <div class="submitted">
      <?php print $submitted; ?>
    </div>
  <?php endif; ?>

  <?php print render($content['links']); ?>

  <?php print render($content['comments']); ?>

</div>

maybe you have the add follow to style.css to .submitted section

.submitted {
  display: inline;
}

your own or style.css

何　wich tags you want inline? you can put tihs at the end of the file

if you use margin then margin-bottom:5px;
you can try padding-bottom:5px;
but 5px is not much
an the taxonomy inline ia haven't looked for

mabe you have set your content types from above to inline