Looking for ideas for a corner patio

I have roughly built an area in a corner of my yard for a corner patio and looking for ideas.

I will install six inch decking boards on top of the retaining walls as well as vertical strips along the sides and corners. The “beds” will be filled with top soil then a fabric and pea gravel on top.

Also thinking about a pergola

Not sure what color to stain the wood or what else to do. Suggestions and ideas would be greatly appreciated.