Feature request: support for transparency / alpha channel

[BoD]

Hi!

My little plugin wants to differentiate between 2 modes: "sleeping" and "active". At the moment when in sleeping mode, I've set the text color to be gray (and default color when active). But on MacOS, the menu bar is actually a semi translucent color which depends on the your desktop wallpaper, and sometimes it can be grayish... and therefore gray text is not very readable.

If instead we could give a transparency or alpha value to the text, that would be ideal.