New features:
- Two built-in themes: Fresh & Clean (cyan) and Monochrome, each in Light and Dark
- Material You support (Android 12+): colours follow your wallpaper
- Theme picker: tap the settings icon (top right) to open a bottom sheet with colour previews

UI polish:
- Typography: DM Sans variable font with correct bold/semibold weights throughout
- EQ curve shadow lines follow the Bézier curve shape instead of being horizontal
- EQ shadow curves and main curve extend flat beyond the outer handles to the view edges
- EQ band labels (Bass / Mid / Treble) horizontally aligned with their control points
