[csswg-drafts] [css-conditional-3] Let's finish the specification (#5315)

svgeesus has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-conditional-3] Let's finish the specification ==
Checking on our oldest/stalest publications, I see:

- CSS Conditional 3: last /TR publication was [2013](https://www.w3.org/TR/2013/CR-css3-conditional-20130404/).
- [Changes since 2013](https://drafts.csswg.org/css-conditional-3/#changes)
- [7 Open/22 Closed Issues ](https://github.com/w3c/csswg-drafts/labels/css-conditional-3)
- [87/88 tests pass](https://test.csswg.org/harness/results/css-conditional-3_dev/grouped/)

Looks like some effort on closing off issues (or deferring hard ones to Conditional 4] and checking test coverage could push this one over the finishing line.

@dbaron I'm happy to help with moving this forward


Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5315 using your GitHub account