.main_div {
	background-color: #FFF;
	width:1000px;
	height:106px;
	background-image:url(image/top_bg.gif);
	background-repeat:repeat-x;
	margin:0px auto 0px auto;
}

.logo_div{
	float:left;
	width:256px;
	height:106px;
}

.ad_div{
	float:right;
	width:728px;
	height:90px;
	margin:8px 8px 0px 0px;
}