electron/electron-api-demos ? reverse-engineered prompt

Build me a desktop app that acts like an interactive showcase for Electron, where people can click through different examples and see both the feature in action and the sample code behind it.

I want it to feel like a polished demo browser with a simple left side navigation, clear sections, and a main content area that explains each example in plain language. It should run on Windows, macOS, and Linux, and it should be easy to launch locally with a normal install and start flow. Please include the basic Electron app structure so someone can learn from the source, and make it straightforward to add new demos later.

If you need to look up current Electron docs online while building it, go ahead. Keep the UI clean and educational, with a strong focus on showing off core Electron APIs in a hands on way.