Vue body style modification

This blog records the App.vue display problem that I encountered when I wrote the project again.

Question : When viewing the page, I found that there is a margin of 8px, which is very uncomfortable. I want to remove this margin.
Before modification: directly above

The solution is to set the style of the body in App.vue through the beforeCreate function

export default {
  beforeCreate() {
    document.querySelector('body').setAttribute('style', 'margin:0;')
  },
}

It can be clearly seen that the margins are gone, over.