You wont see the original css for core components (or any core part of the application) inside studio. Studio is a tool that allows you to override lithium's core code/css with your own, so these areas will be blank unless you add your own code/css there.
Jeff provided the class's of the elements you want to customize. For example if you wanted to move those components to appear to the far left side of the community, you would go into studio > community style > css> and added the following css
#lia-body .lia-content .lia-component-common-widget-user-navigation {float:left;}
Depending with how comfortable and knowledgeable you are with css, you can really go to town customizing the look and feel of your community. Although we encourage that anyone who adds custom code to a community (be it Lithium, the customer or a third party agency) do so while keeping UX best practices in mind so that the end user is a happy user.