It looks exactly the same size in Internet Explorer, Netscape, iCab, Mozilla, OmniWeb and Opera for Windows. I had been influenced by the conventional wisdom, expressed at standards-aware design sites like AListApart. The gurus had said to use pixels, not points, ems or percentages if you wanted control over type size , and I believed them. We were all wrong. I have looked at the CSS specification carefully, and also checked Eric Meyer's new book on CSS2 .
Opera does it right and everyone else does it wrong.
He should know CSS as well as anyone. Pixel units are relative to the resolution of the viewing device, i.e., most often a computer display. If the pixel density of the output device is very different from that of a typical computer display, the user agent should rescale pixel values. It is recommended that the reference pixel be the visual angle of one pixel on a device with a pixel density of 90dpi and a distance from the reader of an arm'slength. For a nominal arm's length of 28 inches, the visual angle is therefore about 0.0227 degrees.