code: private void obtainCardViewElevation() {
          int elevation;
  
          try {
              elevation = ThemeUtil.getDimensionPixelSize(this, R.attr.cardViewElevation);
          } catch (NotFoundException e) {
              elevation = getResources().getDimensionPixelSize(R.dimen.card_view_elevation);
          }
  
          setCardViewElevation(pixelsToDp(this, elevation));
      }
docs: Obtains the elevation of the card view, which contains the currently shown preference
  fragment, when using the split screen layout, from the activity's theme.