We encountered gradients in Chapter 3, Mastering Basic Components, since FMX supports filling implemented through gradients natively. A dedicated data structure, TGradient, is defined in the FMX.Graphics unit. Design-time support has also been added to the IDE to deal with gradients in the Object Inspector window (using a dedicated property editor).
You can think of TGradientAnimation as something that naturally applies the animation concept to two different gradients. Unfortunately, even though FMX supports multi-step gradients, animations don't seem to deal with them properly, so at the moment, it's best to keep the initial and final gradients at the same number of steps.