SOURCE

cola(function(model){
  
});

<h-box style="height:100%">
    <box style="width: 100px"></box>
    <flex-box>
    </flex-box>
    <box style="width: 100px"></box>
</h-box>

v-box > box, h-box > box {
            background-color: rgba(114, 207, 255, 0.56);
        }

        v-box > flex-box, h-box > flex-box {
            background-color: rgba(16, 142, 233, 0.64);
        }