It seems that you can not animate a Brush
in Resources
with Storyboard.Target
. But you can set the Background
of your Style
(you have done this already) and animate this property.
<ColorAnimation Storyboard.TargetProperty="Background.Color"
From="{StaticResource FirstColor}"
To="{StaticResource FinishedColor}"
Duration="0:0:10" BeginTime="0:0:0" />