This is a simple and easy trick. First you need to open your style.css in your template folder and add the following:

[code lang=”css”]

authorstyle { background-color: #B3FFCC !important; }

[/code]

Then you need to open your comments.php which is also located in your themes folder and find the code that looks some what like this:

[code lang=”html”]

<li <?php echo $oddcomment; ?>id=”comment-<?php comment_ID()

?>”></li>

[/code]

Replace it with:

[code lang=”html”]

<li class=”<?php if ($comment->user_id == 1)

$oddcomment = “authorstyle”; echo $oddcomment; ?>”></li>

[/code]