Using DesignScript via C#

Hi, I’m new to programming using Dynamo and my question probably will be silly.
I’m trying to make an interface for my Dynamo script in C# by using some DesignScript functions (in particular Color.ByARGB), but I can’t find this method in Visual Studio. I assume it’s because of lacking reference to some specific library, but I don’t know which one.

So the question is: can I call DesignScript methods using C#? And if so, which library would allow me to call given methods?

cheers,
Matt