Single post in Site Skins: How-To, and Helpful CSS

HI okay so- I've been having some difficulty with a site skin of mine and I've been dying to ask this question. Little disclaimer, I'm a huge newbie when it comes to code because it's kinda hard to process for me, so I may have kind of a hard time piecing things together- sorry!! Is there any way to change the "glow"/"shadow" around certain windows/boxes? Like the subtle glow around the task list and VIP list, or is that just completely tied to the color of the border it's attached to and can't be altered? Thanks so much!! ; ;