hafaio/color-separation — reverse-engineered prompt

Build me a simple browser app for risograph spot color separation. I want to upload an image, pick a few ink colors, and have the app turn the artwork into separate spot color layers that are easy to preview one by one and together. It should feel quick and visual, so I can see how the final print might look and adjust things without needing design software.

Please make it polished enough that someone can just open the site and start separating an image right away. If it makes sense, include a way to export or save the separated results as image files. I’d also love basic zooming and panning on the canvas, since that seems important when working on details.

Keep the interface clean and friendly, aimed at artists or printmakers who are not very technical. If anything is unclear, look up current docs online if you need to, but keep the app focused on risograph style spot color separation rather than turning it into a full editor.