transparent Modalpopup

On an aspx page I have a usercontrol, which has a modal popup.  When the popup gets triggered I would like the user to be able to see the other controls on the page.  How do I set the popup to have a transparent background?

 Here are the two classes that I have:

.modalBackground {

background-color:Transparent;

filter:alpha(opacity='0');

opacity:0.7;

height: 300px;

}

.modalPopup {

background-color: #ffffdd;

border-width:3px;

border-style:solid;

border-color:Gray;

padding:3px;

width: 500px;height: 300px;

}

Thanks.

Read Full article Here.