简单的网页自适应

<h2>简单的网页自适应</h2>
<h3>缩放浏览器查看效果</h3>
<br/>
<div class="city">
<h2>DIV</h2>
<p>占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符</p>
</div>
<div class="city">
<h2>DIV</h2>
<p>占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符</p>
</div>
<div class="city">
<h2>DIV</h2>
<p>占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符占字符</p>
</div>

.city {
float: left;
margin: 5px;
padding: 15px;
width: 300px;
height: 300px;
border: 1px solid black;
}