Drawing with colors?

Does LibreCAD support drawing lines in different colors?  Seems basic, but I couldn't find a command for this.  Searching this forum returned nothing as well.  If not, would it be difficult to patch it in?  

My application requires drawing different building systems (hvac, electrical distribution, electrical devices, etc.) in distinguishing colors and on separate layers.  

Thanks.

Yes, LibreCAD supports drawing lines in different colours.  Either by changing the Attributes of a single entity or by layer.  Refer to these sections in the User Manual:
   https://librecad.readthedocs.io/en/latest/ref/fundamentals.html#attributes
   https://librecad.readthedocs.io/en/latest/ref/tools.html#modify  (See "Attributes")
   https://librecad.readthedocs.io/en/latest/ref/widgets.html#layer-list-dock