How to get an Ionic component by id and change its css style?

I have 2 ionic cards in one page, one is above the other. I want to make some animation effect on the two cards. After swiping away the top, the bottom one moves up to the top and the previous top card moves back and is put under the new top card.
So I want to change the bottomCard z-index to be top or other css styles.

How can I get this component by id? I have searched but haven’t found the way to get it and change the css style on it.