I'm using the Color Block as a background for my Page. I want to add a box-shadow to the Color Block. I can Inspect the element and add it manually 'box-shadow: 10px 10px 10px #653a69;'

I can see the shadow on my Color Block after I add that in the editor. If I go off that page, and back the box-shadow and code are gone. Why? Help please.

Additionally, I'd like to add the same box-shadow property to my Theme CSS instead of adding it on each Page. Can someone tell me if I can do that, and if so, how I do it?

Thanks in advance.