How Would I Reposition Field Text Labels Inside The Entry Fields?

Hello,

My question is whether moving the field text labels so they display ghosted inside the entry field is something that needs to be done via PHP or can it be accomplished via CSS?

For example, on the form on this page, I would like to display the field labels in light gray text inside each field and have the text vanish when the user types any value in the field.

http://worldmoodukkwan.com/evrplus_registration/?action=evrplusegister&event_id=2

Also, I would like to move the fields much closer together on the page so they do not require as much vertical space to display them all.

Are CSS changes or PHP changes or both required to accomplish this?

Thanks!