I'm so glad to hear both the Mt. Lion and your dog are okay.
Some things to consider. A six feet fence is an easy leap for a Mt. Lion. Your dog is simply kibble to a predator. I would never leave a dog or other domestic animals outside, esp. on a long winter's night, alone, in a fenced area, knowing there are predators around: Mt. Lion, Coyotes, etc. Often it is the birds of the night that are the predators we should be concerned about. Your dog could easily be picked up by an owl, etc.
If your dog needs to go out, as all our dogs do, I suggest you take it out on a leash, even in the fenced yard. I do and I also take him slightly beyond, outside the fence, if all feels clear. I go out with a ski pole, headlamp, and a flashlight...even if it's for 5 min. and we do our best to scan the area first, and constantly,...looking for eyes. The pole makes a clear metal sound when it hits the street or rocks.
My former dog and I had a wonderful encounter with the Puma a couple of years ago under the full Snow Moon. My dog was highly trained and calm. So was I. But, things can happen almost in an instant, and I want both the Mt. Lion...or any other animal for that matter, and my dog...and me!...to be safe.
This is the Mountain Lion's home. We are the invaders. We can live together peacefully without, or with a minimum of, incidents, if we are alert and take proper precautions.
The bottom line, always, of course, is that humans are, by far, the most dangerous of all animals. I am always on the lookout for errant humans esp. because they can hide out of sight, carry, and use weapons. Take care.