[Plugin: Wysija Newsletters] Style Error Message

Can’t seem to style the error message.

.formErrorContent {
	background: #000000;
        color: #ffffff;
}

I want to place the error message below my input and submit button which are on the same line and edit the color of it, but it doesn’t seem to be working. How do I fix this?

http://wordpress.org/extend/plugins/wysija-newsletters/