[1] CSS Conditional Rules Module Level 3 ( (2012-12-12 23:06:24 +09:00 版)) <http://www.w3.org/TR/2012/WD-css3-conditional-20121213/>
[2] DOMTokenList's supports() takes a single token · whatwg/dom@a97debc (2016-01-02 11:19:23 +09:00 版) <https://github.com/whatwg/dom/commit/a97debcb4da2c1fc0753ff6fb78638243b5731a3>