Yep it is Bootstrap. Well bootstrap-react to be more precise.

The site was actually built as an experiment on "spec first" coding with AI agents... in this case using Codex CLI. Underlying tech is Typescript, React, Zustard (for state), Bootstrap (for layout/components) and Konva JS (for 2D canvas) and vite for building/bundling. Deployed to AWS S3 bucket fronted by AWS cloud front using Github actions.

I'm planning on adding a video.

Welcome to a whole new obsession!

Nice idea. Will add it to the list

Yeah... I had that tabs/slots and STL on my list but lot priority

It does snap but it was a bit iffy. I have improved it so give it a try.

Re SVG export it is on the list.

Yeah, foam core is easy to work with but a bit thick. The tool does let you set the thickness in the project properties so you may be have some luck setting it to be thinner.

I'll hopefully get a video up soon

Interesting idea. Definitely something I could add.