I wanted to see if it was possible to create SVG charts that would work without JS. Well, it is. I've also created an experimental Svelte component library called Pancake to make these techniques easier to use.
A lovely modern, progressively-enhanced approach to data visualisation that uses primarily SVG, HTML and CSS but can be enhanced with JavaScript for Node-based generation or client-side interactivity, if required. (via @jamesmockett)