yozen0405/bs-cal ? reverse-engineered prompt

Build me a clean web app that helps Brawl Stars players figure out exactly what they need to upgrade a character from one level to another.

I want users to be able to pick a current level and a target level, then see the total resources needed in a simple, easy to read way. It should include the newer upgrade items too, like gadgets, star powers, gears, and hypercharge, not just the basic level costs.

Please make it feel fast and simple to use on desktop and mobile, with a clear calculator style layout and results that update right away when the inputs change. If you need to check current details for the game values or best practice for deployment, look them up online. Also make sure it can run locally and be ready to publish as a static site.