My angry-blood-ghost medication burned out while I was researching this.

As someone who knows very little CSS, all I can concretely say is 'no, it seems folx succumb to elder entities and do animations frame-by-line due to not being able to put at-rules in div-style css chosts. The 'view source' userscript helped me at least figure that much out.'

I'mma stop huffing oracle-fumes now.