superset-frontend/packages/superset-ui-demo/.storybook/themeDecorator.jsx

// themeDecorator.js
import { supersetTheme, ThemeProvider } from '@superset-ui/core';

const ThemeDecorator = Story => (
  <ThemeProvider theme={supersetTheme}>
    <Story />
  </ThemeProvider>
);

export default ThemeDecorator;