浏览器去除内外边距

1.body{margin:0;padding:0} 2.https://www.bootcdn.cn/normalize/ 复制link标签引入 

1.body{margin:0;padding:0}

2.  复制link标签引入 <link href="https://cdn.bootcss.com/normalize/8.0.1/normalize.css" rel="stylesheet">