Edited:
Now that I understand your question, try this…
Place this above your title to enable the post_class function.
<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
Then add </div> below your title (or excerpt, or wherever you want this special styling to end).
Now, a special class will be added in which you can use the classes for post formats. for example, you may now use .format-aside in your CSS to style the aside.