UI Guidelines

Overview

This skill provides comprehensive UI development guidelines for the ludiscan-webapp project. Follow these guidelines to maintain consistency, code quality, and accessibility.

Files in This Skill

• SKILL.md (this file) - Core principles and quick reference
• reference.md - Theme tokens, z-index, and component API reference
• patterns.md - React best practices, TypeScript patterns, and common pitfalls
• examples.md - Code examples for creating components

Core Principles

1. Styling System

ALWAYS use Emotion styled components - NEVER use inline HTML tags

• ✅ Good: const StyledDiv = styled.div...orconst StyledButton = styled(Component)...
• ❌ Bad: <div style={{...}}>

Access theme via useSharedTheme() hook

import { useSharedTheme } from '@src/hooks/useSharedTheme';

const Component = () => {
  const { theme } = useSharedTheme();
  return <Text color={theme.colors.text.primary} />
}

Use theme tokens, not hardcoded values

• ✅ Good: theme.colors.**, theme.spacing.md, theme.typography.fontSize.base
• ❌ Bad: #C41E3A, 16px, 1rem

2. Component Architecture (Atomic Design)

src/component/
  ├── atoms/         # Basic building blocks (Button, Text, Flex, etc.)
  ├── molecules/     # Simple combinations (TextField, Modal, Menu, etc.)
  ├── organisms/     # Complex components (Sidebar, Toolbar, etc.)
  └── templates/     # Page layouts

When to use each level:

• Atoms: Single-purpose, no internal composition (Button, Text, Divider)
• Molecules: 2-3 atoms combined (TextField = Text label + input, Modal = header + content + footer)
• Organisms: Multiple molecules or complex logic (ProjectList, HeatmapViewer controls)
• Templates: Full page layouts with slots for content

3. Component File Pattern

import styled from '@emotion/styled';
import type { FC } from 'react';

// 1. Type definitions
export type MyComponentProps = {
  className?: string;  // Always include!
  // ... other props
};

// 2. Base component - handles logic
const Component: FC<MyComponentProps> = ({ className, ...props }) => {
  return <div className={className}>...</div>;
};

// 3. Styled wrapper - handles styling
export const MyComponent = styled(Component)`
  color: ${({ theme }) => theme.colors.text.primary};
  padding: ${({ theme }) => theme.spacing.md};
`;

Quick Reference

Common Components

Theme Token Categories

Naming Conventions

Critical Rules (Never Violate)

1. ❌ NEVER use any type - use proper types or unknown
2. ❌ NEVER use dangerouslySetInnerHTML - XSS vulnerability
3. ❌ NEVER use inline styles - use Emotion styled components
4. ❌ NEVER hardcode colors/spacing - use theme tokens
5. ❌ NEVER forget className prop - required for styled component compatibility
6. ❌ NEVER overuse useEffect - derive state during render when possible
7. ❌ NEVER create components inside components - define outside
8. ❌ NEVER forget cleanup in useEffect - prevent memory leaks

See Also

• reference.md - Complete theme tokens and API reference
• patterns.md - React best practices and TypeScript patterns
• examples.md - Full code examples for new components