要在style.css里面放上两个这样的代码，需要怎么操作啊

/**首页特效begin**/
.navtab{clear:both;height:27px;}
.navtab li{float:left;width:79px;border:1px solid #7DABD5;border-left:none;text-align:center;line-height:24px;height:24px;cursor:pointer;}
.navtab .active{border-bottom:1px solid #F8F9FC;background:#F8F9FC;font-weight:bold}
.navtab #tab_t1{border-left:1px solid #7DABD5;width:83px;}
.navContent{border:1px solid #7DABD5;border-top:none;clear:both;margin:0 0 5px;background:#F8F9FC;height:150px;}
.navContent ul.textList{width:320px;clear:both;padding:8px 0 0;}
.navContent ul.textList li{padding-left:20px;clear:both;background:url(/images/newsli.gif) 10px 7px no-repeat;text-align:left;line-height:22px;}
.navContent ul.textList li span{float:right;}
.navContent ul.ztlist{float:left;width:280px;padding:5px 0 0;}
.navContent ul.ztlist li{float:left;width:131px;padding-left:18px;background:url(/images/newsli.gif) 10px 50% no-repeat;text-align:left;line-height:22px;height:22px;overflow:hidden;}
.navContent ul.list1{float:left;width:280px;padding:5px 0 0;}
.navContent ul.list1 li{clear:both;padding-left:18px;background:url(/images/newsli.gif) 10px 8px no-repeat;text-align:left;line-height:22px;}
/**首页特效End**/

复制到你所说的那个文件里就行。

楼主，我建议你先花一个星期（或者不到）学学CSS