src/lib/createEmotionCache.ts

import createCache from '@emotion/cache'

const isBrowser = typeof document !== 'undefined'

export default function createEmotionCache() {
  let insertionPoint

  if (isBrowser) {
    const emotionInsertionPoint = document.querySelector<HTMLMetaElement>(
      'meta[name="emotion-insertion-point"]'
    )
    insertionPoint = emotionInsertionPoint ?? undefined
  }

  return createCache({ 
    key: 'mui-style', 
    insertionPoint,
    prepend: true 
  })
}