Card colors & font fix

@Ollie and I decided to go with more neutral to make it a bit more professional looking (instead of green, blue, red). I think it makes sense to offer color templates for the carousel

• define "default light" for the light color (pearlbrush500) and
• "event dark" for dark color (with white text/pill).

for later:

• "default dark"
• "event light"
• the chance pic a free color for a card.