Looking at the website, I'm at work on OSX, so can't download... but it's unclear if this is free, open-source or commercial software... the marketing of this page/site is pretty hard to tell, and hideous overall.<p>If it's commercial the lack of any pricing or licensing information leads me to want to avoid at all costs... I'm assuming it's a commercial product, and it's completely not clear short of giving your email address to download.
C# has some advantages over JS but Xaml styles and templates are so much easier than CSS.<p>Around 2010 when I was a WPF dev moving back to web I looked so hard for a tool that would do this.<p>I'm guessing this renders as SVG but CSS (mainly flexbox) and tools have improved so much that it's not needed so much now.<p>Still going to have a good look into it though.