By default, a CSS transition is __
one-sided, so that there is only one transition and it goes from the end state to the initial state.
symmetric, so that the transition going from the initial state to the end state is the reverse of the transition going from the end state back to the initial state.
one sided, so that there is only one transition and it goes from the initial state to the end state.
asymmetric, so that the transition going from the initial state to the end state is different from the transition going from the end state back to the initial state.