Can anyone guess what CSS styling I should apply to a button to guess this exact look.

Note: I realize this is the default look for for unstyled buttons on Windows and that I don’t have to apply any CSS to get this style, but on Mac and Linux it’s not the same, so I can’t depend on the default styling of the OS for this. I would have to force this style myself in the css. Anyone knows what CSS styling can consistently produce this effect?
Examples
Firefox 3.6.12
Safari 5.0.3
Chrome 8
Internet Explorer 8
For some reason, IE8’s propriety
filterproperty didn’t work (it should).HTML
It seems to work better cross browser with 2 child elements. Using the
buttonitself as the outer element caused a few issues.CSS
See it on jsFiddle.