CSS-Tricks didn't get paid $4m. They got acquired. The previous owner of CSS-Tricks got $4m.
Got acquired => got paid. CSS-Tricks the entity (up to the point of acquisition) got paid the money. If and how the money was divided between the people involved doesn’t seem be public info.
Got acquired => got paid. CSS-Tricks the entity (up to the point of acquisition) got paid the money. If and how the money was divided between the people involved doesn’t seem be public info.