This style forces any specific Chinese sites to use Microsoft JhengHei / Yahei font regardless of the site css . Firefox has a setting for specifying font for web page encoding but the setting is overridden by site specific css.

Why need this:

On Windows prior to Vista (XP / 2000), the default font for traditional / simplified Chinese is MingLiu (細明體) / SimHei (黑体) which looks very edgy and not very too legit, not the mention that they ain't clear type (ie: doesn't take advantage of sub-pixel rendering on LCD monitors)

Starting from Vista, MS has included a much better set of ClearType fonts called Microsoft JhengHei (正黑體) and YaHei (雅黑体) as default fonts for traditional / simplified Chinese. XP user can download and those fonts from Micorsoft:

MS JhengHei - http://www.microsoft.com/DownLoads/details.aspx?familyid=87E726A9-5C79-4A73-9347-78A557314D0B&displaylang=en
MS YaHei - http://www.microsoft.com/downloads/details.aspx?FamilyID=b15774c0-5b42-