When talking about CSS-in-JS I am reminded of the short lived escapade at Netscape around 1997/1998 when they launched JSSS, only be be shut out by Microsoft ignoring support for it in the increasingly dominant Internet Explorer as they favored CSS. As a result it died and disappeared.
http://sunsite.uakom.sk/sunworldonline/swol-04-1997/swol-04-...