comments.php

if($comment->user_id == 1){ echo '<span class="admin_author">管理员回复</span>'; };

.admin_author {
    background:url(images/admin.gif) no-repeat right center; width:60px;
    height:41px;
    position:absolute;
    left:60%;
    bottom:5px;
    text-indent:-9999px; // 注：需要admin_author的父层添加position:relative;
}