body {margin:0 auto;overflow:hidden;}  

/*=============第一页=============*/	
.header{
	margin:0 auto;
	width:100%;
	height:640px;
	background-color:#000;
	position:relative;
	}
.header canvas {
	width:100%;height:auto/*默认全屏显示 可自己设置高度640px*/;
	display:inline-block;vertical-align:baseline
	position:absolute;
	z-index:-1;
	}
.header .canvaszz{  /*用来解决视频右键菜单，用于视频上面的遮罩层*/
	width:100%;
	background-image: url(img/in_top_bj.jpg);
	height:640px;
	position:absolute;
	z-index:10;
		filter:alpha(opacity=40);  
      	-moz-opacity:0.4;  
      	-khtml-opacity: 0.4;  
      	opacity: 0.4;
	}

.audio{ 
/*设置音乐显示位置*/
	width:45px;
	position:fixed;top:65px;left:94%;
	z-index:100;
	filter:alpha(opacity=30);  
      -moz-opacity:0.3;  
      -khtml-opacity: 0.3;  
      opacity: 0.3;
	}
.header .top_logo{
	background-image: url(img/top_logo.png);
	margin:0 auto;
	width:750px;
	height:200px;
	position:absolute;
	z-index:30;
	top:10px;
	left: 50%;
	margin-left: -390px;
	}	

.header .nav{
	width:804px;
	height:auto;
	position:absolute;
	z-index:30;
	top:420px;
	left: 50%;
	margin-left: -400px;
	}
.header .nav a.gv { 
	text-decoration:none; 
	background:url(img/nav_gv.png) repeat 0px 0px; 
	width: 130px; 
	height: 43px; 
	display: block; 
	text-align:center;		/*水平居中*/
	line-height:43px;  /*上下居中*/
	cursor:pointer;
	float:left;/*左浮动*/
	margin:8px 2px 8px 2px;
	font:18px/43px 'microsoft yahei'; color:#066197;
	}
.header .nav a.gv span {
	 display: none;
	 	
}
.header .nav a.gv:hover { 
	background: url(img/nav_gv.png) repeat 0px -43px; 
	color:#1d7eb8;
	-webkit-box-shadow: 0 0 6px #1d7eb8;
	transition-duration: 0.5s;
	}
	
.header	.topcn{
	width: 980px;
	top:200px;
	left: 50%;
	margin-left: -490px;
	position:absolute;
	z-index:20;

	}