xxxxxxxxxx<html><head> <title>W3.CSS(w3cschool.cn)</title> <meta name="viewport" content="width=device-width, initial-scale=1" charset="UTF-8"> <link rel="stylesheet" href="https://7npmedia.w3cschool.cn/w3.css"></head><body><div class="w3-container w3-center"> <h2>中心内容</h2> <img src="https://atts.w3cschool.cn/img_car.jpg" alt="car" style="width:80%;max-width:320px"> <p>w3-center 类将元素居中。</p></div></body></html>