Purpose of "UNKNOWN" selector in some style sheets

I have noticed the presence of declarations like this:

UNKNOWN {
height: 30px
}

in the style sheets used by some highly regarded CSS folks. This
declaration usually (but not always) follows a declaration ending with
"voice-family: inherit."

I assume this is some CSS hack, but I can't find anything on the web
discussing this declaration.

Thanks

In article <a8f6562e.0407210829.3a8e27a (AT) posting (DOT) google.com>,
roboaks (AT) comcast (DOT) net (Rob Oaks) wrote:

I have noticed the presence of declarations like this:

UNKNOWN {
height: 30px
}

in the style sheets used by some highly regarded CSS folks. This
declaration usually (but not always) follows a declaration ending with
"voice-family: inherit."

My guess is that you're looking at a CSS file you saved to your hard
drive, and that furthmore you saved it using IE/Win, probably but not
necessarily IE5.5 or earlier. When you save a style sheet via IE/Win,
it doesn't save the actual file on the server you've visited, but
instead saves a dump of the style sheet as it's represented within IE's
DOM. If you want to see what people are really doing in their style
sheets, go to the actual CSS file on the server and save that.
And it sounds like you're seeing the results of the Box Model Hack
(http://tantek.com/CSS/Examples/boxmodelhack.html) confusing the browser.

--
Eric A. Meyer (eric (AT) meyerweb (DOT) com) http://www.meyerweb.com/eric/
Principal, Complex Spiral Consulting http://www.complexspiral.com/
"CSS: The Definitive Guide," "CSS2.0 Programmer's Reference,"
"Eric Meyer on CSS," and more http://www.meyerweb.com/eric/books/