Hello! Here is a triforce lightbox that i made. For the gray and the blue, you can use the same shade as i have made the darker portion thicker so it appears dark when light is on it. Or, like in the image provided from the slicer, you can update each color to have one dark and light. All borders are separate objects so you are able to pick and choose how you would like it.
able to mount on wall, cable routing provided through the bottom or back if you prefer to stand it up.
For lightstrips, i prefer this one because i like the manual switch. On my color lightboxes i prefer just a white or yellow light instead of the full RGB ones: https://www.amazon.com/dp/B0BYJ8MW2T?ref=ppx_yo2ov_dt_b_product_details&th=1.
The alternative (RGB) with controller and all that is this: https://www.amazon.com/dp/B07MMNH5HH?ref=ppx_yo2ov_dt_b_product_details&th=1.
I am not affiliated or anything so if you find anything better please let me know! Also drop a comment and let me know how it is! Thanks