clarxxinn/Modern-Calculator ? reverse-engineered prompt

Build me a modern Android calculator app that feels clean and simple, with the whole interface made in Jetpack Compose.

I want it to behave like a real calculator, so it should handle addition, subtraction, multiplication, division, decimals, sign change, clear, and backspace. It needs to follow normal math rules for order of operations, not just calculate left to right. The expression should update live as I type, with commas for large numbers, and the result should only show when I press equals. If I keep going after getting a result, it should continue from that answer like a real calculator.

Please also include a light theme and a dark theme that can be switched from the top menu, plus a fullscreen mode that hides the system bars. Make it look polished with Material 3 styling, rounded buttons, and a simple modern layout. If you need current setup details, look up the latest Android docs online.