CSS styling for submit button

I’m trying to style my contact form. This is what I have:

.pbSubmit{
	text-align:center;
	width:100%;
	background-color:#3399cc;
	color:white;
}
.pbSubmit:hover{
	opacity:75%
}

The css works, except the text color and background color wont change. They are still the default black and gray

Thanks!