Be sure to watch your RGBs... If the main distinction between two colors is in RG, you have a likely issue. Of course, there are other sorts of color-blindness too. On the other hand, there's a bit of technology fail: CSS is well enough designed to allow users to absolutely override website text colors, but it does not provide any conditional overrides (e.g., if the colors are too close according to my personal formula, modify thus). There may be more sophisticated techniques available to more sophisticated users, but I'm not sure.