You should edit assets\default\css\theme.css file:body { background: url('../images/page_bg.png') top left repeat-x #c8c8c8;}#container { background: #fff; width: 840px; margin: 0 auto; box-shadow: 0 0 6px rgba(0, 0, 0, 0.5); -moz-box-shadow: 0 0 6px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 0 0 6px rgba(0, 0, 0, 0.5);}Remove " background: url('../images/page_bg.png') top left repeat-x #c8c8c8;" to remove background image.Remove box-shadow: 0 0 6px rgba(0, 0, 0, 0.5); -moz-box-shadow: 0 0 6px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 0 0 6px rgba(0, 0, 0, 0.5);to remove border