전역 theme 설정

pages/_app.tsx
에서

import '../styles/globals.css';
import theme from '../styles/globals'
import { ThemeProvider } from 'styled-components';
import GlobalStyle from '../styles/globals';

function MyApp({ Component, pageProps }) {
  return (
  <ThemeProvider theme={GlobalStyle}>
    <Component {...pageProps} theme={theme}/>
    </ThemeProvider>
    )
}

export default MyApp;

import { ThemeProvider } from 'styled-components';
import GlobalStyle from '../styles/globals';

두개를 import 해주고

  <ThemeProvider theme={GlobalStyle}>
    <Component {...pageProps} theme={theme}/>
  </ThemeProvider>

Thmeprovider 로 감싸서 theme을 전역으로 내려줘야한다.