*{
	margin:?0px;
	padding:?0px;	
	font-size:?12px;
}
body
{
	background-color:#F5F5F5;
}
.top
{
	width:?100%;
	height:?27px;
	background:?url(../images/top_bg.jpg)?repeat-x;
}
.top_content
{
	width:?1000px;
	margin:0?auto;
}
.top_content?li
{?
	list-style-image:?url(../images/li_bg.gif)?;
????float:?right;
	width:70px;
	line-height:?27px;
}
.top_content?a:link,.top_content?a:visited
{
	color:?#8E8E8E;
	text-decoration:?none;
}
.top_content?a:hover,.top_content?a:active
{
	color:?#900;
	text-decoration:?none;
}
.wrap
{
	width:?1000px;
	margin:?0?auto;
}
.logo
{
	height:?80px;
	background-color:?#FFF;
}
.logo_left
{
	width:?200px;
	float:?left;
}
.logo_right
{
	width:?300px;
	height:?28px;
	float:?right;
	margin-top:?26px;
	color:?#8E8E8E;
}
.logo_right?img
{
	vertical-align:?middle;
	margin-right:?10px;
	
}
.tel
{
	
	font-family:"微軟雅黑";
	font-size:?18px;
	color:?#CC0000;
	
	
}
.nav
{
	height:?40px;
}
.nav_left
{
	width:?10px;
	background:?url(../images/nav_left.jpg)?no-repeat;
}
.nav_mid
{
	width:?980px;
	background:?url(../images/nav_bg.jpg)?repeat-x;
}
.nav_right
{
	width:?10px;
	background:?url(../images/nav_right.jpg)?repeat-x;
}
.nav_left,.nav_mid,.nav_right
{
	height:?40px;
	float:?left;
}
.nav_mid_left,.nav_mid_right
{
	
	float:?left;
}
.nav_mid_left
{
	width:?680px;
}
.nav_mid_right
{
	width:?300px;
}
.nav_mid_left?li
{
	float:?left;
	list-style:?none;
	width:?100px;
	text-align:?center;
	line-height:?40px;
}
.nav_mid_left?a:link,.nav_mid_left?a:visited
{
	text-decoration:?none;
	color:?#FFF;
	font-size:?16px;
	font-family:?"微軟雅黑";
}.nav_mid_left?a:hover,.nav_mid_left?a:active
{
	text-decoration:?none;
	color:?#FF0;
	font-size:?16px;
	font-family:?"微軟雅黑";
}
.search_text
{
	width:?190px;
	height:?25px;
	margin-top:?7px;
	background:?url(../images/search.jpg)?no-repeat?right?center;
	background-color:?#fff;
	padding-right:?25px;
	border:?none;
}

各位大神請看一下這是怎么回事，在線等

所寫的代碼與與視頻教程相同，但“首頁”顯示位置不在左側，這是為什么？