Acrylic sheet to replace skylight bubble?

Once I bought a used MH and the po had replaced bathroom skylight with a flat piece of plastic/acrylic. As I recall they had build a frame to raise the sheet off the roof just a bit. I think the reason was to allow for the headroom lost when you remove the inner and outer bubble. May not be a problem if skylight is not in the shower. What are your plans to dress up the hole on the inside.

I think “curb” should read “curve”. I’m not sure it matters as I don’t believe the bubbles have a curved bottom.