Стилизованные компоненты сброшены

import { createGlobalStyle } from 'styled-components'

const GlobalStyle = createGlobalStyle`
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
`

// in your app root
<React.Fragment>
  <GlobalStyle />
  <Navigation /> {/* example of other top-level stuff */}
</React.Fragment>
Excited Eland