How does thunkable it's DnD responsive web app work?

[sketch]

Hi everyone this may sound a bit silly.
But last week i was wondering how Thunkable it’s DnD Ui is able to resize to diffrent screen sizes.
So my qeustion is:
How does it work?
Thanks!

[muneer]

First switch the view to the table view.

Click on “Preview” icon and you should see the window where you have the option to Preview as a responsive web app.

[sketch]

That’s not what i’ve meant.
I mean how does it like resize the buttons, image, labels etc