mans70q/lumo ? reverse-engineered prompt

Build me a clean, polished Flutter app called Lumo.

I want a simple starter app that runs well on iPhone, Android, and web, with a nice first impression and a solid basic structure so I can keep building on it later. Please set up a home screen with a modern, friendly look, sensible spacing, and a smooth responsive layout that works on different screen sizes. If it makes sense, include a basic theme, splash screen, and app icon so it feels like a real product instead of a default template.

Keep the code organized and easy to extend, and make sure the project builds without issues. Add a simple example screen or placeholder content so the app does something visible right away. If you need to check current Flutter setup details or best practices, feel free to look them up online.