Begining from

http://jigsaw.w3.org/css-validator/#validate_by_input+with_options

and choosing to show all warnings and filling the form with the following three lines of CSS code

#s {background-color: #330; color: #fff; }

#v {background-color: #999; color: #000; }

#s, #v {text-align: center; }

often (but not always !) triggers one (or two) color warning(s) such as:

URI : TextArea

1 #s You have no color set (or color is set to transparent) but you have set a background-color. Make sure that cascading of colors keeps the text reasonably legible.

Pressing the back-button in the browser and making a new try often changes the number of warnings.

When testing with the last line removed, no warning is shown.

I've tried several web browsers and different language settings, but the problem remains.