背景引入多张图片

background:   url('/safetystatic/resources/images/naturalDisaster/header_top.png')no-repeat top, 
                      url('/safetystatic/resources/images/naturalDisaster/header_footer.png')no-repeat bottom,
                      url('/safetystatic/resources/images/naturalDisaster/header_body.png')repeat-y center;

 background-size: contain;
 background-color: rgba(0,0,20,0.8);