*{
    margin: 0;
    padding: 0;
}
.bar_nav{
    border-bottom: 1px solid #ccc;
    margin: 10px auto;
    text-align: center;
    width: 1000px;
    height: auto;
}
.bar_nav h3{
   /*  font-weight:normal;
    line-height: 50px; */
    
    font-size: 20px;
    text-align: center;
    font-weight: normal;
    margin-bottom: 20px;
    margin-top: 10px;
}
.section_main{
    width: 940px;
    height: auto;
    margin: 15px auto;
    overflow: hidden;
}
.section_main ul li{
    float: left;
    width: 450px;
    height:320px;
    list-style: none;
    margin-top: 20px;
    position: relative;
    overflow: hidden;
}
.mag_right{
    margin-right: 40px;
}
.position_top{
    position: absolute;
    width: 450px;
    height: 50px;
    top:270px;
    left: 0px;
   background: rgba(0,0,0,0.7);
    z-index: 8;
    color: #fff;
    font-size: 22px;
    line-height: 50px;
    padding-left: 50px;
    box-sizing: border-box;
}
.position_top img{
    width: 20px;
    height: 20px;
   position: absolute;
    top: 15px;
    left: 15px;

}
.position_but{
    width: 450px;
    height: 270px;
    position: absolute;
    top: 0px;
    left: 0;
    background: rgba(0,0,0,0.5);
    color: #fff;
    font-size: 18px;
    line-height: 380px;
    text-align: center;
}
.position_but img{
    width: 80px;
    height: 80px;
    position: absolute;
    top:50%;
    left:50%;
    margin-top: -40px;
    margin-left: -40px;
}
.img{
    width: 450px;
    height: 320px;
    transition:all 1s linear;
}
.sec_ul li:hover .img{
    -webkit-transform: scale(1.5);
    -moz-transform: scale(1.5);
    transform: scale(1.5);
}
.sec_ul a{
    width: 450px;
    height: 320px;
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    z-index:100;
}
.nav {
	
}

.nav a {
	position: relative;
	display: inline-block;
	margin-right: 30px;
	text-decoration: none;
	color: #00BCFD;
	font-size: 18px;
	font-weight: 700;
	padding-bottom: 8px;
}

.nav a:after {
	content: "";
	position: absolute;
	bottom: 0;
	right: 0;
	width: 0;
	border-bottom: 3px solid #00BCFD;
	transition: all linear 0.5s;
}

.nav a:hover {
	color: #00BCFD;
}

.nav a:hover:after {
	left: 0;
	width: 100%;
	transition: all linear 0.1s;
}