如何使用v4版本styled-components的全局样式？

1.首先需要安装V4版本的styled-components，由于v4版本废除了injectGlobal的使用，所以创建方式应该改为如下方式：

import { createGlobalStyle } from "styled-components";

//css全局样式，reset.css
export const GlobalStyle = createGlobalStyle`
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}
`;

2.在app组件中按如下方式使用：

import React from 'react';
import Header from "./common/header";
import { GlobalStyle } from "./style";

function App() {
  return (
    <div className="App">
        <GlobalStyle/>
        <Header/>
    </div>
  );
}

export default App;