为什么我没有自适应
<!DOCTYPE html>
<html>
<head>
<!-- <meta charset="UTF-8"> -->
<title>moblie</title>
<style type="text/css">
.box {
width: 100%;
height: 100px;
background-color: red;
}
.inner {
width: 25%;
height: 100px;
background-color: blue;
}
</style>
</head>
<body>
<div class="box">
<div class="inner">
</div>
</div>
</body>
</html>
