UI Components

Write React components in src/ui/ following the project's component philosophy.

Requirements

• File naming: PascalCase (e.g., ItemCell.tsx)
• CSS file: Paired .module.css file (e.g., ItemCell.module.css)
• Delegate logic to hooks and utils

Pattern

import classNames from 'classnames/bind';
import type { ReactNode } from 'react';

import styles from './ComponentName.module.css';

const cx = classNames.bind(styles);

interface ComponentNameProps {
  children: ReactNode;
  variant?: 'primary' | 'secondary' | undefined;
  isActive?: boolean | undefined;
}

export function ComponentName(props: ComponentNameProps): ReactNode {
  const { children, variant = 'primary', isActive = false } = props;

  return (
    <div className={cx('component', `component--${variant}`, { 'component--active': isActive })}>
      {children}
    </div>
  );
}

CSS Module Pattern

/* ComponentName.module.css */
.component {
  padding: var(--space-md);
  background: var(--bg-surface);
  border: 1px solid var(--border-default);
}

.component--primary {
  color: var(--text-primary);
}

.component--secondary {
  color: var(--text-secondary);
}

.component--active {
  border-color: var(--accent-primary);
}

Rules

1. Check existing components first - Look for Button, Panel, Text, Flex, Icon before creating new ones
2. Use primitive components - Compose with Box, Flex, Text, Button, Panel, Icon
3. CSS variables only - Use design tokens, not hardcoded values
4. BEM naming - .block-element--modifier in CSS
5. Delegate logic - Complex logic goes in hooks/utils, not components
6. No helper functions - Extract to utils if needed

classnames Binding

Always use classnames/bind for conditional classes:

import classNames from 'classnames/bind';
const cx = classNames.bind(styles);

// Good
<div className={cx('cell', { 'cell--selected': isSelected })} />

// Bad - plain string literals forbidden
<div className="cell" />
<div className={styles.cell} />

Design Token Prefixes