.main_btn{
	width:647px;
	height:286px;
	background:url(../images/btn/mainbtn_back.png) no-repeat;
	background-position: center bottom;
	position:absolute;
	left:10px;
	overflow:hidden;
}

.cover{
	width:194px;
	float:left;
}
.main_btn>.cover:nth-child(2){
	margin:0 32px;
}

.two_co{
	margin:0 32px;
}

.cover>a{
display:inline-block;
}

.cover>a>img{
	-webkit-transition:all 0.5s;
	-moz-transition:all 0.5s;
	transition:all 0.3s;
}


.cover a:hover>.img1_1{
	opacity:0;
}

.img1_1{position:absolute; top:0; z-index:2}
.img1_2{position:relative; top:0; z-index:1; opacity:0;}

.cover>a:hover>.img1_2{
		opacity:1;
	}