I need ideas

Hello everyone! I am in search of ideas..

We are closing on a house in less than 2 weeks. A big deciding factor in this property was the already fenced in back yard. It is a typical white vinyl fence. However, the property is on a slight slope. Each panel is level, stepping down at each post. This leaves me with a 12"-16" gap at the lowest point in the yard, between the panel and the ground. I am looking for recommendations on what would LOOK NICE, to cover said gap. I understand I could just purchase pressure treated lumber and lay it down in front. But, I am after something more appealing to the eye. There are dogs that I am concerned will use their curious side, and try to get out between that gap.

We've been toying around with the idea of a raised garden bed around the perimeter, but I don't think the vinyl fence would support that kind of weight on it, and dirt would still spill out the other side.

Any recommendations will be taken back to the council (The lady). I appreciate any and all recommendations!