You are better doing it by RadWindow. You can definitely achieve this by overriding CSS style of Telerik Edit Form.
HERE IS THE STYLE
.rgEditForm table {
/*CHANGE FONTS*/
font: normal 13px 'Your Font',Arial,Helvetica,sans-serif !important;
line-height: 22px !important;
/*CHANGE BACKGROUD - FACEBOOK'S BLUE*/
background-color: #3B5999 !important;
}