Css change box postion

box.css

#blockContainer {
display: -webkit-box;
display: -moz-box;
display: box;
-webkit-box-orient: vertical;
-moz-box-orient: vertical;
box-orient: vertical;
}
#blockA {
-webkit-box-ordinal-group: 2;
-moz-box-ordinal-group: 2;
box-ordinal-group: 2;
}
#blockB {
-webkit-box-ordinal-group: 3;
-moz-box-ordinal-group: 3;
box-ordinal-group: 3;
  
/****************************************/
  
.container {
display:flex;
flex-direction: column-reverse;
}
.section1,
.section2 {
height: auto;
}