The reasons: 1. There are some bad markup errors on the plugin page (not closed p,b tags) 2. The plugin doesn't care about e107 HTML/CSS standards and W3C validation from what I saw. 3. CSS customize is not possible because all styles are inline (hardcoded).
Solution: If there is template which could be overridden from the theme folder - do it and clean the mess. If not - nothing could be done.
e107 Bulgaria | Corllete Lab