No support for Kai and Fangsong generic font families

• Component: Text
• Status: NEW ---

[Fuqiao Xue]

There are many font styles used in Chinese composition, but Song, Kai, Hei, and Fangsong are the most important ones.

The `font-family` CSS property should support generic family names for these font styles.

More: https://www.w3.org/TR/clreq/#four_commonly_used_typefaces_for_chinese_composition

`generic(kai)` and `generic(fangsong)` are not supported by WebKit.

css-fonts-4 describes `generic(kai)` and `generic(fangsong)` in CSS: https://drafts.csswg.org/css-fonts-4/#generic-font-families

The Kai and Fangsong generic font families significantly improves the fallback mechanism of Chinese websites and web applications. If the browsers does not support them, the differences expressed by the font styles won't appear (unless the developer use web fonts, which is often too large).

### Tests & results

Interactive test, [font-family:generic(kai) will apply a Kai font in Chinese](https://github.com/w3c/character_phrase_tests/issues/62)

Interactive test, [font-family:generic(fangsong) will apply a Fangsong font in Chinese](https://github.com/w3c/character_phrase_tests/issues/25)

### CSS issue

https://github.com/w3c/csswg-drafts/issues/4606 (closed)

[Radar WebKit Bug Importer]

<rdar://problem/119593224>