Cinziasart on "[Theme: Customizr] Customize background of individual pages/posts"

Hello! I would like to change the background (color or background image) on a couple of pages only. Can anybody please help? I changed the default background already this way:
body {
background: #FFFF99;
background-image: url(image);
background-position: center center;
background-repeat: no-repeat;
background-attachment: fixed;
}

Thanks!