html,body {background: url(../images/bg.png) repeat-x left top; width:100%;height:100%; 
}
 
.i_top_bg{width:100%;height:auto; background: url(../images/top_bg1.png) no-repeat top center; margin:0px auto; }
.i_top_jg{width:100%;height:249px;}

.i_top_nav{width:100%; height: 28px; margin:0px auto;}
.i_top_nav2{width:100%; height: 25px; margin:0px auto; }

.i_left_jg{height:100%;width:22px;}
.i_b{width:100%;height:auto; margin:0px auto;}