How to define floating responsive cards?

Ionic Framework ionic-v3
1

Hi,
I have four small cards (A,B,C,D) into an Ionic app.
I’d like to show them as A,B,C,D (on the same line) or as
A,B
C,D
depending on the device orientation or the size of the page like a responsvie site.
How can make these cards responsive without bootstrap?

Thank you very much.

cld

2

I’ve seen I have to put the cards into a Responsive Grid.