Design Token Theme
Component Detail
Description
Flutter ThemeData extension exposing the project's design token system (colors, typography, spacing, radii) as typed Dart constants. Used by certification status badge, alert banner, and all status indicator widgets to ensure consistent visual language across the app.
design-token-theme
Summaries
The Design Token Theme component ensures that every visual element across the application adheres to a consistent, professional visual language defined by the product team. By encoding colors, typography, spacing, and shape into typed Dart constants, it eliminates ad-hoc styling decisions that create visual inconsistencies and increase maintenance costs over time. A consistent design system directly improves user trust and perceived product quality, which is particularly important in accessibility-focused applications serving users with visual impairments. It also accelerates feature development by giving engineers a shared vocabulary for UI decisions, reducing back-and-forth with designers and shortening review cycles.
The Design Token Theme is a foundational shared component with no external dependencies, making it suitable for delivery in the earliest sprint alongside other infrastructure work. Its low complexity means it can be defined incrementally: start with the status color tokens needed by the certification badge and alert banner, then expand to typography and spacing as those UI components are built. The main risk is token naming conventions being changed mid-project, which would require updates across all consuming components. Establishing and freezing the token API early prevents this.
Light and dark mode token mapping adds a small scope increase that should be accounted for in estimates if dark mode is a launch requirement rather than a post-launch enhancement.
Implemented as a Flutter ThemeExtension or a static AppTokens class with const fields. Status color tokens (statusActive, statusWarning, statusExpired, statusPaused) should be semantic rather than raw hex values, mapping to the design system's intent rather than specific colors to enable theming. The spacing and radius methods take typed enums (SpacingScale, RadiusScale) and return double values, preventing arbitrary magic numbers in layout code. textStyle returns TextStyle instances from the typography scale.
For light/dark mode support, use ThemeData.extension and MediaQuery.platformBrightness or Flutter's ThemeMode to switch token sets. All widget files that previously used hardcoded colors or TextStyles should be migrated to AppTokens references. This component has no Riverpod dependency and does not require asynchronous initialization.
Responsibilities
- Expose semantic color tokens (success, warning, error, surface, primary)
- Provide typography scale tokens (labelSmall, bodyMedium, titleLarge)
- Expose spacing and radius tokens for consistent layout
- Support light and dark mode token mapping
Interfaces
AppTokens.statusActive
AppTokens.statusWarning
AppTokens.statusExpired
AppTokens.statusPaused
AppTokens.spacing(SpacingScale scale)
AppTokens.radius(RadiusScale scale)
AppTokens.textStyle(TextScale scale)