What problem does it solve? Flutter apps with a custom visual identity often end up with hardcoded colors, broken dark mode, and deprecated Material 2 APIs scattered across widgets. This Skill provides a canonical, single-source-of-truth approach to Material 3 theming so colors, typography, and component styling stay consistent, accessible, and rebrandable. ## Core Features & Use Cases - Seed-based color schemes: Derive light and dark palettes from one brand seed with ColorScheme.fromSeed, including DynamicSchemeVariant.fidelity for vivid brand colors. - Dark mode wiring: Configure theme, darkTheme, and themeMode on MaterialApp, and read platform brightness correctly with MediaQuery.platformBrightnessOf. - Brand tokens via ThemeExtension: Define custom spacing, radii, and brand colors with const constructors, copyWith, and lerp so themes animate across light/dark transitions. - Typography and component themes: Set a TextTheme ramp once and tune cards, app bars, and inputs with the current *ThemeData classes instead of per-widget styling. - Use Case: When building a new Flutter app with brand guidelines, use this Skill to create lib/core/theme/app_theme.dart with a seed-derived ColorScheme, an AppSpacing ThemeExtension, and a system-following dark mode, then verify with flutter analyze. ## Quick Start Ask the agent to set up Material 3 theming for your Flutter app with a brand seed color, dark mode support, and custom spacing tokens in lib/core/theme.
