<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
*{
padding: 0;
margin:0;
}
html,body{
height: 100%;
}
.app{
background: #ccc;
100%;
height: 100%;
display: flex;
flex-flow: column;
margin: 0 auto;
}
header{
100%;
background: rgb(255,0,0);
height: 60px;
}
main{
100%;
background: blue;
flex: 1;
display: flex;
}
aside{
200px;
background: cadetblue;
}
article{
flex:1;
background: yellow;
}
footer{
100%;
background: rgb(0,255,0);
height: 100px;
}
</style>
</head>
<body>
<div class="app">
<header></header>
<main>
<aside></aside>
<article></article>
</main>
<footer></footer>
</div>
</body>
</html>
使用flex：1，可以填充空白部分