background verdiğiniz elemente
display:flex;flex-direction:column;justify-content:space-between;
verin
örn :
<div style="display:flex;flex-direction:column;justify-content:space-betweeen;background:black;color:white;">
<div>
Üst Taraf
</div>
<div>
Alt Taraf
</div>
</div>