Liferay has two unstyled themes which are supposed to be used as the foundation for theme development. These two themes, named styled and unstyled, have no real CSS behind them but provide the basic foundation for creating a new theme (they provide many of the placeholders that a theme developer would populate to affect the whole look and feel of the portal).
I'm not sure what your default theme is, but if you changed off of 'classic' (or any other fully populated theme) or you created a brand new theme based upon either the styled or unstyled themes, you end up w/ the page as presented in your screen capture.
To change the appearance of Liferay, you need the SDK and create a theme project. The new project would use styled as the default parent theme, but I usually use classic as my parent theme. After you have the theme project, you can start overriding the appropriate CSS files to change the look and feel.
Please sign in to flag this as inappropriate.