*{
margin:0;
padding:0
}
body, html, .body{
height:100%;
width:100%;
}
.body{
display: flex;
flex-direction: column;
}
.box1{
display: flex;
justify-content: space-between;
align-items: center;
height:50px;
line-height:50px;
background:red;
color:#fff;
}
.content{
display: flex;
flex: 1;
overflow-y: auto;
}
.footer{
height:50px;
line-height: 50px;
background:blue;
text-align: center;
}
.header1, .header3{
width:10%;
vertical-align: middle;
line-height: 50px;
text-align: center;
}
.header2{
width:80%;
text-align: center;
}
html
<div class="body">
<div class="box1">
<div class="header1"><</div>
<div class="header2">容</div>
<div class="header3"></div>
</div>
<div class="content">内容</div>
<div class="footer">底部</div>
</div>
