Numio is a clean, minimal calculator built with Kotlin and Jetpack Compose. No ads, no tracking, no internet permission — it never needs to talk to the outside world. Features: * Clean, minimal design with retro circular keys * Live results — see the answer as you type * Scrollable expression display, so long numbers are never truncated * Calculation history saved locally with a Room database * Built-in unit converter — Length, Weight, Area, Volume, Temperature, Time, Speed, Pressure * Theme customization — 12 preset accent colors plus custom hex input * Your chosen theme color is remembered across sessions * Hand-drawn custom app icon * A small hidden easter egg * 100% offline — nothing ever leaves your device This is a first solo project, built from scratch and open-sourced so anyone can use, inspect, or contribute to it.