这是介于语法高亮和无样式之间的一种样式，效果如图：
CSS参考
图一
pre {
margin:15px auto;
padding:20px 15px;
border:1px solid #ddd;
border-left:4px solid #58749c;
background:#fbfbfb url(img/prebg.png) repeat;
white-space:pre-wrap;
word-wrap:break-word;
letter-spacing:1.5px;
font:13px/25px 'Comic Sans MS','courier new';
line-height:22px;
background-size:100% 44px
}
图二
pre {
color:#444;
margin:15px auto;
padding:20px 15px;
border:3px dashed #ddd;
border-left:8px solid #bbb;
background:#fff url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABMAAAAmCAIAAACphTeFAAAAJElEQVRIx2N4RS5gGNU5qnNU56hOZJ2fyQWjOkd1juoc1YkMAKDL4lkok3p7AAAAAElFTkSuQmCC') repeat;
white-space:pre-wrap;
word-wrap:break-word;
letter-spacing:1.5px;
font:14px/25px 'Comic Sans MS','courier new';
line-height:22px;
background-size:100% 44px
}
需要到图一的背景图片下载：点击这里。图二是base64图片
