Hello! I have been working on my palette making skills and need a bit of help!

I have made the background opacity lower so that it is transparent and you can see the background through it. The problem is that extra boxes such as my about this stable, images(stable avi and banner included) are also somewhat seethrough which I do not want. I want the boxes layered on top of the background background(the box surrounding this box) to be visible and not transparent but want to keep the base background(in the palette editor it is called the page background color) to be transparent.

I know that I probably need to add a Z index but I am unsure of how I can do that when the basic coding of the website can not be changed but the elements(for example palettes) can be changed. I will post some screenshots below for you all to see. Thank you all!