Styling the browser itself

Is this allowed for in any part of the specifications? For an example of
what I'm talking about, open this page in Chrome:
http://www.ineedwebpage.com/ and look at the scrollbar. I am trying to
figure out if this is possible in any other browsers (haven't checked
safari, but it should work, as it has a -webkit prefix), as well as if there
might be an easier (read: non-prefixed) way of doing this (now or in the
future).

The particular code for this is this:

::-webkit-scrollbar {

width: 11px;
height: 11px;

}

::-webkit-scrollbar-track {

background: -webkit-gradient(linear, left top, left bottom, from(#4A4A4A),
to(#333333));
box-shadow:inset 0 0 10px #000000;

}

::-webkit-scrollbar-thumb {

background: -webkit-gradient(linear, left top, left bottom, from(#333333),
to(#222222));
box-shadow:inset 0 0 10px #000000;

}

::-webkit-scrollbar-resizer {

background-color: #333333;

}