To access the style properties for Holidays: Winter, navigate to ACP → Appearance → Styles & Templates → Style Properties → [TH] Holidays: Winter.
The following components are able to be styled:
Avatar
Category strip left (odd)
Category strip center (odd)
Category strip right (odd)
Category strip left (even)
Category strip center (even)
Category strip right (even)
Navigation bar left
Navigation bar center
Navigation bar right
Block container styling (odd)
Block container styling (even)