Description:

This decoration is very closely modelled on the fvwm2 crystal style,
it's main asset is transparency.

It has a sleek and simple design, but it has (pseudo) TRANSPARENT
titlebar, buttons and borders. The style can use the current colors
for the title bar and blends it with the background image of the
desktop, or just play around with the brightness and intensity of the
background image. You can define the amount of shadeness for the
active and inactive window (all between fully transparent and fully
opaque).