Why css nesting isn't supported?

[balmy fjord]

I'm genuinely curious

[shut swan]

?

css nesting isnt supported on templatestyles because it is more strict

[mystic flare]

I have a request for you @shut swan Please wait with marking it done until the user responds and/or acknowledges. Otherwise if users respond with another question, it might get missed.

[balmy fjord]

I think we're talking about different things. I meant this nesting:

.class1 {
  & .class2 {
  }
}

[grave obsidian]

https://battlecats.miraheze.org/wiki/MediaWiki:Global.css#L-695 works here

not exactly what you've written but it is nesting

[tawny summit]

If you write this syntax on MediaWiki:Common.css or User:<Username>/common.css then MediaWiki likes to spit out a warning but you can ignore the warning and just save the page.

After which the nesting CSS will work as expected

you should be aware that & nesting has only about 90% global usage though, so some older browsers may not render the CSS correctly (in which case the blame wouldn't be on the wiki software or platform)
https://caniuse.com/?search=%26+nesting

[balmy fjord]

It didn't let me save

[tawny summit]

If you write it on a page like Template:<some filename>.css then it wouldn't let you save

This is because TemplateStyles is stricter on CSS nesting

[balmy fjord]

oh