双飞翼布局

flex实现建议双飞翼布局，话不多说，开撸！！！

html

    
header
    

        
left
        
container
        
right
    
    
footer

css

*{
  margin:0;padding:0;border: none;
}
header,footer{
  height:50px;
  background: #ddd;
}
.main{
  display:flex;
}
.content{
  flex-grow:1;
  height:400px;
  background:gold;
}
.left,.right{
  width:100px;
  background: green;
}