Hello, got get some help, new to Garden

#garden.types.CSSAtRule{:identifier :media, :value {:media-queries {:min-width "640px"}, :rules ([:.container {:max-width "640px"}])}} => for what purpose garden.types.CSSAtRule are used?

Looks like an implementation detail for any css rules that start with @. Things like media queries. You can see about those here. https://github.com/noprompt/garden/wiki/Media-Queries