Change the color of the error messages at signup [Social Theme]

When users try to signin on the Social theme and make a mistake.. let's say an invallid e-mail adres.. Then the error message is as grey as the rest of the text.

I like this to be red..
So in the global.css file I tried to add this at line 278.

color:#C00;

But it made everything red.
How can I make this for the error message only? Is this possible?