<item name="android:actionModeBackground"> lets you set the background color of the native action mode. I have not used action modes with
appcompat-v7 personally; last I checked, they did not support them, forcing you back to the native implementation.
There may be recipes for changing the fonts. I have never changed the fonts in the action bar, let alone in the action mode, and so I do not know the details. From a brief scan of the docs, you might hunt around Stack Overflow or elsewhere for
actionModeMenuStyle attributes for use in style resources.