I understand your frustration, as I was having the same problem viewing the text through firefox etc, as it was too light.
The color of the text is not the problem, it is actually a dark grey at it's source.
The opacity of the text is the problem. It causes the dark grey text to become very light.
Follow Siobhan's advice posted above, and in your css plugin add the lines:
The opacity range is between 0 and 1. Set it to 1 and it will be a regular string of text with a dark grey color. You can also follow the above advice to change the color if you wish, but I believe the opacity is the source of your frustration. Anywhere in the CSS code you have an opacity you can set it to 1 and it will solve your problem.
I understand the theme creator having a opacity set like it is, but for some of our pages that element just goes too far. Good luck!