div {
display: flex;
flex-direction: column;
justify-content: space-between;
}
.top {
height: calc(100% - 200px);
}
.bottom {
flex: 0 0 200px;
}
<div class="flex row">
<span class="t2 flex column">
<em class="t1"></em>
<em class="t2"></em>
</span>
</div>
.flex {
display:flex;
}
.row {
flex-direction:row;
}
.column {
flex-direction:column;
}
.t1 {
flex:1 1 100%;
}
.t2 {
flex:1 1 200px;
}
div {
width:100%;
height:100vh;
background:blue;
}
.flex.column {
background:red;
}
.column .t1 {
background:green;
}