20241003 - Use CSS Modules for Styling

Status

• Proposed
• Accepted
• Rejected
• Deprecated
• Superseded

Context

Frontend styling approaches significantly impact development efficiency, maintainability, and performance. Our project required a styling solution that meets the following requirements:

1. Design System Consistency - Effective management of design tokens for a unified UI
2. Implementation Efficiency - Leveraging Figma style export to accelerate development
3. AI Utilization - Maximizing AI-assisted coding support
4. Code Quality - Preventing conflicts through scoped styling

We considered the following options to meet these requirements:

• CSS Modules
• Tailwind CSS
• CSS in JS

Decision

We have decided to adopt CSS Modules as our styling approach. The key factors behind this decision are:

1. Stability and Future-Proofing with Standard Technologies

• Standard CSS Specification - Most stable styling approach using direct CSS
• Immediate Access to New CSS Features - Seamless utilization of features like CSS Variables
• Tool Chain Compatibility - Standard support in major bundlers (Webpack, Vite)
• Technology Longevity - Long-term viability independent of frameworks

2. Efficient Design System Implementation

• Consistent Design Token Management - Global variable management via CSS Variables
• Direct Figma Integration - Efficient conversion from design to CSS
• Easy Theme Switching - Simplified dark mode implementation through variable changes
• Rapid Design Change Propagation - Changes in one place affect the entire system

3. Team Development Optimization

• Parallel Development via Component Isolation - Independent work areas through scoping
• Automatic Name Collision Avoidance - Component-level CSS modularization
• Minimal Learning Curve - Development possible with standard CSS knowledge only
• Code Review Simplification - Improved readability through separation of styles and logic

4. High Compatibility with AI-Assisted Coding

• High-Precision Generation Based on Standard Specifications - Improved code generation accuracy
• Abundant Reference Information - Leveraging global information as learning data
• Predictable Structure - Streamlined debugging and modifications
• Adaptation to Future AI Technology Evolution - Continuous improvement expected for standard technologies

5. Balance Between Performance and Quality

• Build-Time Optimization - Reduced runtime overhead
• Easy Code Splitting - Component-level code splitting
• Caching Strategy - Efficient caching design
• Bundle Size Optimization - Automatic elimination of unnecessary styles

Consequences

Positive Impacts

1. Design Quality and Consistency

   • UI unification through design tokens
   • Visual coherence between components
   • Simplified multi-theme support

2. Development Productivity

   • Accelerated implementation from direct Figma export
   • Enhanced development efficiency through AI assistance
   • Parallel development at component level

3. Code Quality

   • Prevention of style conflicts through scoping
   • Clear responsibility separation at component level
   • Predictable style application

4. Technical Stability

   • Long-term maintainability through standard technologies
   • Tool chain compatibility
   • Performance optimization

Negative Impacts

1. UI Component Library

   • Lack of compatibility with Tailwind CSS-based libraries (shadcn/ui, etc.)
   • Development and maintenance costs of custom UI component libraries
   • Additional effort for third-party integration

2. Style Sharing and Global Management

   • Complexity in designing shared styles between components
   • Need for special management of global styles
   • Construction of style override strategies

3. Team Adaptation Costs

   • CSS Modules convention adoption
   • Promoting understanding of the design token system
   • Maintaining consistent implementation style

Technical Flexibility

1. Possibility of Gradual Evolution

   • Room for combining with other technologies in the future
   • Tolerance for different approaches in specific components
   • Natural adaptation to standard CSS evolution

2. Development Environment Interoperability

   • Integration with TypeScript
   • Standard integration with CI/CD environments
   • Compatibility with existing tool chains