set transparency using theme roller

Question

I'm using Theme Roller, and I need one of the buttons to have 85% transparency. I was able to set the value in Theme Roller to include the transparency : #D9ffffff but when I test it I am getting an Invalid Property Value on the resulting css:

background-color: #D9ffffff;

What should the syntax be?

Answer 1

I was able to edit the uncompressed copy of the downloaded theme and change the background color to the rgba value, here it is with the fallback color:

background-color: #ffffff  /*{c-bup-background-color}*/;
background-color: rgba(255, 255, 255, .85)  /*{c-bup-background-color}*/;