Transparent Theme For The New Nova Design

[Autumn-6517]

When you try to use the Alpenglow theme on the latest Firefox Nightly build, the sidebar is transparent due to the way the theme works, since the theme only covers the top portion of the window. I'd love if this transparent effect was made into an official theme put with the redesign. So instead of having a color or a picture or anything else over the window, it is just the transparent sections that has been added to the design. Below is what the sidebar with the Alpenglow theme looks like currently.