Hi Siva,
I have tried the mentioned use-case in a sample app.
Check this: Mobile View | Tablet View
Widget Tree View:

CSS Snippet:
.outerCntr {
height: 100%;
text-align: center;
font-size: xx-large;
padding: 8% 7% 15%;
}
.firstCntr {
border: 1px solid green;
height: 40%;
}
.secondCntr {
border: 1px solid blue;
height: 30%;
}
.thirdCntr {
border: 1px solid brown;
height: 30%;
}
.contentMiddle {
display: flex;
justify-content: center;
flex-direction: column;
margin: 0% 0% 3%;
}
Note: I didn't include any inline CSS style for this implementation.
Let me know, in case if you need the .oml file for reference.
Hope this helps you!
Kind regards,
Benjith Sam