adding a simple css change to the minimalist for everything gmail module

[Jason Michael]

I would like the new gmail (with tabs) to stop showing the big ugly grey box when the tab is empty - or, more appropriately, just make the opacity of that box .1 rather than .9, as it is now.

here's what I start with:

When I do this css change:

I get this effect:

So I added to the gmail module in minimalist like this:

but it doesn't work.

Why?