.ui-dialog .ui-widget-header {
    background-image: url(http://www.werkenbijdeloitte.nl/img/topbg.jpg);
}
.ui-dialog .ui-widget-header.ui-corner-all {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border: none;
    color: white;
}
.ui-dialog .ui-dialog-buttonpane {
    border-top: 1px solid #92d400;
}
.ui-dialog .ui-dialog-buttonpane .ui-corner-all {
    border-top-left-radius: 5px 5px;
    border-top-right-radius: 5px 5px;
    border-bottom-left-radius: 5px 5px;
    border-bottom-right-radius: 5px 5px;
}
.ui-dialog .ui-dialog-buttonpane .ui-state-default,
.ui-dialog .ui-dialog-buttonpane .ui-state-hover {
    background-image: none;
    background-color: #008fd5; 
    color: white;
    font-weight: bold;
    border: none;   
}