Combo chart custom theme - how to code line color

[Annlen]

Hi All ,

I am trying to create a custom theme. All goes good apart form customizing default color for line color in combo chart. 

Can anyone advice how I can set up default color for bars and line in combo chart type?

Additionally, can anyone point me to the documentation listing css classes which we could use for extra customization. 

Thank you in advance, 

Anna