Using a secondary button style in the case of binary actions

[giomfo]

n the case of simple binary actions (yes/no), it would be useful to differenciate the main action from the secondary action button using two different buttons styles.
This is the case for invitations, where currently Accept or Reject look exactly the same.
Element uses a button and a simple text. We could do the same thing, only using our colors.

We should be able to restore the current Element-Android style