This is a great explanation of the difference between the [lang] and :lang CSS selectors. I wouldn’t even have thought’ve the differences so this is really valuable to me.
In which Matthew disects a multiple choice quiz that uses CSS to do some clever logic, using the :checked pseudo-class and counter-increment.
Oh, and this is how he realised it wasn’t using JavaScript:
I have JavaScript disabled on my phone because a) it cuts out most of the ads, b) it cuts out lots of bandwidth and I have a limited data plan, and c) my battery lasts longer because it’s not processing tons of code to show me some text (cough, Medium).
A really interesting proposal from Lea that would allow CSS authors to make full use of selectors but without increasing specificity. Great thoughts in the comments too.