How exactly do you use the new themes and neo look?

[tedivm]

This blog post, which is linked to from the official mermaid diagram docs, introduces a new look and several new themes.

I've tried using them locally and they literally just don't work. When I looked in the themes directory of the code I noticed that the theme files aren't there.

Do these themes and the neo look actually exist? Was this blog meant to preview functionality that is coming in the future, or some sort of private offering through MermaidCharts where it wasn't made clear it's not part of the open source project?