You should be able to just copy the code in chrome that is the decider for the form and put your class in front of it. Example below for a form and disabled form.
Code:
.myCssClass input{
	background-color: lightblue;
}


.myCssClass.Web_Disabled input {
    background-color: red;
}

It's kinda like your locks, but if you look careful it is not so hard really.