Change color node on sources in dbt docs

The problem I’m having

I would like to change the color node on all the sources in my dbt project. Is there a way to change this? Or is it just always green by default?

The context of why I’m trying to do this

All my sources are in my silver layer, but in the documentation they appear as green as per default.

What I’ve already tried

> models:
>   sources: 
>     +docs: 
>       node_color: "#A0A0A0"

Some example code or error messages

Nothing happens when I put this in.