(colortheme) What's the name of that element

[weber]

Hello people.
I know it's quite a lame question to ask, but this is one of the rare
things I don't know how to find out in emacs... (or google)
I'm messing with color themes, and I haven't been able to change the
color of what I would call "margins": they are the vertical spaces
both at left and right edges (it's just a blank space, no text..). If
you have scroll bar on, it's just before it... you know what I'm
talking about! Help me! :)
Thanks in advance,
weber

(PS: Is there a function that returns me font-lock-comment-face when
i'm at a comment, font-lock-number-face when i'm at a number, etc... i
mean: a function that returns me syntactic info of the current
element ? Ps tks)