Very neat idea! I like the different color palettes available. You can see how a slight change in a shade can have a lot of impact.
I think the experience could be vastly improved by using CSS Variables (Custom Properties): you can update all the colors with JS in a single click (even the colors embedded in SVGs). That way, the color swap would be instant (no page reload) but you could still provide a direct sharing URL by replacing the state of the URL in the address bar.
I think the experience could be vastly improved by using CSS Variables (Custom Properties): you can update all the colors with JS in a single click (even the colors embedded in SVGs). That way, the color swap would be instant (no page reload) but you could still provide a direct sharing URL by replacing the state of the URL in the address bar.