Text colour for most of the site is dark green but may vary in different areas (e.g. here in the 'technical' area where, as you have probably noticed, it's black) Backgrounds may have a faint picture such as silver-green leaves, mushrooms or cogs, or be plainer such as a paper effect background or even a plain white background . As a rule of thumb, menu backgrounds have pictures such as silver-green leaves, mushrooms, etc, my articles have the same picture but lighter (lighter so as not to interfere with the words) and articles written by other authors will have a paper effect background (and black text - not including external links to other sites, obviously). While green text and a leafy background is the most common combination, text colours and backgrounds do vary in different areas of the site as I have said, but in any case the text should always be a set colour rather than simply your PC's automatic/default.
If the background or any other picture does not have good resolution you may want to change your colour options, e.g. 256 colours replaced with High Colour or True Colour via the Display Settings on your Control Panel.
Note to other web-developers: - if you are going to leave the text colour as automatic/default then you should really have the background colour automatic/default too. Let me know if you can't figure out why.