本文主要介绍了详解css3 flex弹性盒自动铺满写法，分享给大家，具体如下：
<style type="text/css">
.flexcontainer{
width:100%;
height: 100%;
position: absolute;
left:0px;
top:0px;
display: flex;
flex-direction: column;
}
.flex1 {
width: 100%;
height: 8rem;
float: left;
background: #f00;
}
.flex2 {
width: 100%;
height: 4rem;
flex:1;
float: left;
background: #000;
}
.flex3 {
width: 100%;
height: 7rem;
float: left;
background: #ccc;
}
</style>
<div class="flexcontainer">
<div class="flex1"></div>
<div class="flex2"></div>
<div class="flex3"></div>
</div>