The color chosen will be the text (font) color for your tabs and accordion body - the main content area.
This setting in combination with the 'header font color' gives 2 color font schemes to your templates.
In the case of tabs, the 'body font color' also affects the headers: The non-active tabs will get this font color as well (while the active tab will get the 'header font color').
Have a look at the color schemes demo for examples of how these colour combinations come together.
Body text color setting is a basic configuration option.
Here is the list of all basic configuration options.