I use flex to show top, center, bottom, and I want inner div id=flex_child_center_overflow_div to be scrollable in flex_child_center div. But the result is not as expected, the flex_child_center_overflow_div show full screen.
http://jsfiddle.net/oudioppa/Ld0h3xer/3
<div id="root" style="position:absolute;top:0;left:0;right:0;bottom:0;">
<div id="flex_container" style="height:100%;display:flex;flex-direction:column;">
<div id="flex_child_top" style="height:50px;background-color:yellow;"></div>
<div id="flex_child_center" style="flex:1;background-color:blue;display:block;">
<div id="flex_child_center_overflow" style="height:100%;background-color:lightgreen;overflow-y:auto;">
<div id="flex_child_center_overflow_div" style="height:1000px;background-color:lightblue"></div>
</div>
</div>
<div id="flex_child_bottom" style="height:50px;background-color:green;"></div>
</div>
</div>