Quick way to completely backup an edited theme?

Hi:

I’ve made extensive changes to the Relaxation 3-column theme and have finally validated everything. Now…. How do I back up my hybrid theme files so that if one gets corrupted again somehow, I can just re-upload them all?

Is there some quick, magical way to do this that preserves folder heiarchy, or do I have to select and save each file one at a time? (I hope there’s a quicker way.)

Thanks.