样式设置高度撑bai满整个页面，那么必须从最外层，一层一层设置高度100%；
<html lang="en"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <title>Document</title> <style> * { padding: 0; margin: 0; box-sizing: border-box; } html, body, div { height: 100%; } .app { background: #ccc; } </style> </head> <body> <div class="app"></div> </body> </html>
</div>
