Google Treemap - Differentiate between -ve (negative) and +ve (positive) values

[Sachin Bal]

Hi,

I have created a TreeMap. I have defined 

         tree.draw(data, {

                         minColor: '#f00',

                         midColor: '#ddd',

                         maxColor: '#0d0',

                         }

This does not show clearly +ve values in green or shades of green and -ve values in red or shades of red. How can I achieve this?

Thanks

Sachin