pre 宽度样式

pre {
 white-space: pre-wrap; /* css-3 */
 white-space: -moz-pre-wrap; /* Mozilla, since 1999 */
 white-space: -pre-wrap; /* Opera 4-6 */
 white-space: -o-pre-wrap; /* Opera 7 */
 word-wrap: break-word; /* Internet Explorer 5.5+ */
}