Align checkbox with text in comments form

I have added a wee "notify me of new comments" checkbox on my comment form, but cannot get the box to align with the text; it is always centred on the line below.

Is there a way that I can get the checkbox to show up next to the text?

Example page here: http://ift.tt/1gmjonN

<div class="commentform">
{exp:comment:form channel="blog" entry_id="{structure:page:entry_id}" parse="inward"}
<label for="name">Your name</label>
<input type="text" name="name" value="{name}">
<label for="email">Your email address</label>
<input type="email" name="email" value="{email}">
<label for="url">Your website (if you have one)</label>
<input type="url" name="url" value="{url}">
<label for="comment">Your comment</label>
<textarea name="comment" id="comment" value="comment" rows="8"></textarea>
<label for="checkbox">Notify me of follow-up comments?</label>
<input type="checkbox" name="notify_me" value="yes" {notify_me}/>
<input type="submit" name="submit" value="Submit" id="comment-submit">
{/exp:comment:form}
</div>