CSS1
Cascading Style Sheets, level 1
1996-12-17: W3C勧告
https://www.w3.org/TR/REC-CSS1-961217
1996-01-11: 改訂
https://www.w3.org/TR/1999/REC-CSS1-19990111
2008-04-11: 改訂
https://www.w3.org/TR/2008/REC-CSS1-20080411/
2018-09-13: 廃止
https://www.w3.org/TR/2018/SPSD-CSS1-20180913/