Improve colors used on the Gantt chart (I can't see the light grey/blue)

Some of the auto-selected colors used on the gantt chart aren't really visible to me. There is a light grey/white color being used against a very light background. It's terrible. I have to keep toggling the choice to color by different methods so that I can see them again. But then sometimes I really need a particular option that is using the light grey color.