This is copied from above, but condensed slightly and re-written in semantic terms. Note: #Container
has display: flex;
and flex-direction: column;
, while the columns have flex: 3;
and flex: 2;
(where "One value, unitless number" determines the flex-grow
property) per MDN flex
docs.
#Container {_x000D_
display: flex;_x000D_
flex-direction: column;_x000D_
height: 600px;_x000D_
width: 580px;_x000D_
}_x000D_
_x000D_
.Content {_x000D_
display: flex;_x000D_
flex: 1;_x000D_
}_x000D_
_x000D_
#Detail {_x000D_
flex: 3;_x000D_
background-color: lime;_x000D_
}_x000D_
_x000D_
#ThumbnailContainer {_x000D_
flex: 2;_x000D_
background-color: black;_x000D_
}
_x000D_
<div id="Container">_x000D_
<div class="Content">_x000D_
<div id="Detail"></div>_x000D_
<div id="ThumbnailContainer"></div>_x000D_
</div>_x000D_
</div>
_x000D_