At the moment it's not possible to change the appearance of your profile.
But we are working on a theme editor where you can create your own style or select from pre-defined themes.
Before we enable it, we want to make sure it works perfectly fine though. Also keep in mind that we want to keep some control over the appearance of our web site because we want to keep it neat and tidy. We also want to avoid potential problems with broken HTML and CSS, also for security reasons.