CSS problem for a widget submit button

Hi,

I’m working on my new blog and I’m having a problem customizing a submit button of the “subscribe2” plugin (labeled “ABONNEMENT” in french). I first thought it was due to the plugin but when I inspect the code with Chrome, it tells me that the background-color is taken from this code section:

@media screen and (min-width: 59.6875em)
.widget button, .widget input[type="button"], .widget input[type="reset"],.widget input[type="submit"], .widget_calendar tbody a {
background-color: #ffffff;

It seems rather strange because the dimension of the screen I use is bigger (min-width: 77.5em). In fact, this code is generated in the head section of the index and I don’t know how to get rid of it.
Here’s the code I put in my CSS style sheet, but it’s not taken into account :

.subs2 input[type="submit"] {
		background-color : #B2B2B2;
		color : #fff;
	}

(subs2 is the class for the subscribe2 widget)

Could somebody help me change the background-color and the color ?

Regards,

Joaquim.