Custom Markdown Container Support

[cameroncf]

I notice that there are some custom markdown containers that are typically fenced by three colons for things like "error", "warning", and "info" aren't working in the demo. I'm very new to Astro and to this theme (which is lovely by the way) and am wondering if this is a bug or just an unsupported artifact leftover in the demo?

The live demo also doesn't appear to render them properly.