Changing colors of dual axis chart

I've found few posts very helpful in terms of chart customization in Design Studio. I have a very specific question pertaining to 'Column Combination - Dual Axis' chart type.

I have 4 values displayed by Chart - Column.

I need that the color will change according to the value. for example :

column 1 :      smaller then 30- green

                      between 31to 60 - orange

                      bigger then 61 - red

column 2 :     smaller then 15- green

                      between 16 to 30 - orange

                      bigger then 31- red

Is it possible ? if it is- how ? CSS?

Im using DS 1.5

I would really appreciate if someone can help me out.

ROB