[Plugin: Constant Contact for WordPress] Style for "Sign up" submit button color

I am trying to simply change the button background color of the “sign up” button, and can’t figure out the correct css to customize this. I’ve tried all of these, none are working:

.input#constant-contact-signup-submit {
background-color: #cccccc;
color: #cccccc;
}

#constant_contact_api_widget-3 .button submit {
background-color: #cccccc;
color: #cccccc;
}

#constant-contact-signup-submit input {
background-color: #cccccc;
color: #cccccc;
}

.button submit input{
background-color: #cccccc;
color: #cccccc;
}

Any help is much appreciated! I included the whole section that contains the Constant Contact widget in the footer:

<div id="footer" class="sidebar-no">
        <div class="group inner footer_row_1 footer_cols_3">            

			<div id="constant_contact_api_widget-3" class="widget-1 widget-first widget constant-contact-signup"><h2>Stay Updated</h2><form action="http://suzannekatanic.com/beta/" method="post" id="constant-contact-signup" name="constant-contact-signup">
					<label for="cc_firstname">First Name:</label>
					<div class="input-text-wrap">
						<input type="text" name="fields[first_name][value]" id="cc_firstname" value="" />
					</div>
					<label for="cc_lastname">Last Name:</label>

					<div class="input-text-wrap">
						<input type="text" name="fields[last_name][value]" id="cc_lastname" value="" />
					</div>
				<label for="cc_email">Email:</label>
				<div class="input-text-wrap">
					<input type="text" name="fields[email_address][value]" id="cc_email" value="" />
				</div>Contact Lists:<div class="input-text-wrap"><ul>
<li><label for="cc_newsletter-1"><input type="checkbox" name="cc_newsletter[]" id="cc_newsletter-1" class="checkbox" value="1" /> General Interest</label></li>

</ul>
</div>

				<div>

					<input type="hidden" id="cc_referral_url" name="cc_referral_url" value="http%3A%2F%2Fsuzannekatanic.com%2Fbeta%2F" />
					<input type="hidden" id="cc_redirect_url" name="cc_redirect_url" value="" />
					<input type="submit" name="constant-contact-signup-submit" value="Signup" class="button submit" />
				</div>
			</form></div>

http://wordpress.org/extend/plugins/constant-contact-api/