slint-ui/slint ? reverse-engineered prompt

Build me a polished open source GUI toolkit demo site and sample app that shows what Slint can do.

I want a simple declarative UI experience where the interface is written in .slint and connected to app logic, with a clean hello world example, a widget gallery, and a few small demos like a counter, a form, and a responsive layout that works nicely on desktop and in a browser. Make it feel native and lightweight, with good looking controls, sensible spacing, and a smooth preview workflow so I can edit the UI and see changes quickly.

Please wire it up so it’s usable from Rust, and leave the structure flexible enough that other supported languages can plug in too. If you need current docs or examples, look them up online. Focus on making the app easy to run, easy to understand, and nice enough to show off as a first impression of the toolkit.