LineageOS/android_packages_apps_ExactCalculator — reverse-engineered prompt

Build me a clean Android calculator app like the standard LineageOS Exact Calculator.

I want it to feel simple and reliable for everyday use. It should open quickly, show a big readable display, and have the normal calculator buttons for numbers, decimal, clear, delete, equals, plus, minus, multiply, divide, parentheses, percent, and common scientific functions if they fit naturally. The important part is that the math should be accurate and not surprise the user with weird rounding for normal calculations.

Please make it look like a real system app, with a neat layout that works on different screen sizes and supports dark mode if possible. Keep the code organized in Java for Android, with proper resources, strings, colors, and an Android manifest. It should be buildable with Gradle in a normal Android project.

If anything is unclear, choose the simplest behavior that matches a stock Android calculator. Look up current Android docs online if you need to.