In postbit(_legacy), find:
HTML Code:
<if condition="$show['moderated']">
<td class="alt2" id="td_post_$post[postid]">
<else />
<td class="alt1" id="td_post_$post[postid]">
</if>
Replace with:
HTML Code:
<if condition="$show['moderated']">
<td class="alt2" id="td_post_$post[postid]">
<else />
<if condition="is_member_of($post, X)">
<td class="YOUR_CLASS" id="td_post_$post[postid]">
<else />
<td class="alt1" id="td_post_$post[postid]">
</if>
</if>
Replace "X" in "<if condition="is_member_of($post, X)">" with your Admin/Moderator usergroups.
Replace YOUR_CLASS with your own CSS class.