Many plugins deal with key colors. They do so in a homogeneous way. Colors can be specified in one of the following formats:

• RRGGBBAA: four hexadecimal values, specifying red, green, blue and alpha values in that order. Red, green and blue go from 00 for off to ff for full power. Alpha goes from 00 for fully transparent to ff for fully opaque. For example, ff7f007f specifies a half-transparent, vivid orange.
• RRGGBB: three hexadecimal values, specifying red, green, blue values in that order. Same as before, except color is always fully opaque.
• name: one of W3C-defined extended color keywords. Always fully opaque.
• logitech: the exact string logitech. Specifies color 00cdff, fully opaque. This is the default color used by Logitech keyboards if no software controls them.

Starting with release 0.6, invalid color specifications are usually replaced with opaque black, to allow a smoother experience when live-reloading the configuration.