Add compact mode transparency

[dnred]

Disabled	Enabled

The glassy/mica blur effect looks really good and it should also be there when compact mode is enabled.

[Glypse]

I agree and would love to see this implemented, same goes for the floating URL bar, I would love to see that get transparent. This non-transparent behavior is how the browser behaves on all OSs (MacOS, Windows, Linux) ; I believe that to make this suggestion gain more traction, you could rename it to something like "Compact Mode Transparency" (since the Mica effect is Windows-only, but this suggestion regards all platforms) or "More transparent elements" (if you think the URL bar should be transparent as well, for example).