vw,vh实现手机端布局 -

html代码如下：
```html
<!DOCTYPE html>

<html lang="">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>vw,vh实现手机端布局</title>
</head>
<style>
body {
margin: 0px;
}
.box1 {
width: 80vw;
height: 20vh;
background-color: darkgoldenrod;

}
.box2 {
  width: 80vw;
  height: 60vh;
  background-color: darkorchid;
}
.box3 {
  width: 80vw;
  height: 20vh;
  background-color: darkred;
}
.center {
  margin: auto;
  border-radius: 0.5em;
  font: bold 2rem "微软雅黑";
  text-align: center;
}

</style>
<body>
<div class="box1 center">头部区</div>
<div class="box2 center">内容区</div>
<div class="box3 center">尾部区</div>
</body>
</html>

```