.navs {
	width: 1200px;
    height: 70px;
    left: 50%;
    margin-left: -473px;
    top: 948px;
    position: absolute;
}
.nav1, .nav2, .nav3, .nav4 {
	width: 193px;
	height: 193px;
	margin-right: 50px;
    display: block;
    float: left;
}
 .nav1:hover, .nav2:hover，.nav3:hover，.nav4:hover {
cursor: pointer;
}
.nav1:hover, .nav2:hover, .nav3:hover, .nav4:hover {
	margin-top: -10px;
}
.nav1 {
	background: url(../image/btn1_1.png) no-repeat;
}
.nav1:hover {
	background: url(../image/btn1_2.png) no-repeat;
}
.nav2 {
	background: url(../image/btn2_1.png) no-repeat;
}
.nav2:hover {
	background: url(../image/btn2_2.png) no-repeat;
}
.nav3 {
	background: url(../image/btn3_1.png) no-repeat;
}
.nav3:hover {
	background: url(../image/btn3_2.png) no-repeat;
}
.nav4 {
	background: url(../image/btn4_1.png) no-repeat;
}
.nav4:hover {
	background: url(../image/btn4_2.png) no-repeat;
}