This strange hack makes it possible to quickly update the style of all DataCardKeys and DataCardValues in a Power Apps form. Normally its simple to update multiple controls at once. Just select a group of controls then change the desired problem.
Read more in the Blog Post:
Power Apps hack!
Unfortunately Power Apps doesn't allow multiple selection of form controls across multiple cards. If you want to change the style in one go it can be very time consuming. Here I show you a trick for achieving simultaneous editing of form controls to quickly edit the appearance of your Power Apps forms.