.tran_1 {
    transition: all 0.3s ease 0s;
    -ms-transition: all 0.3s ease 0s;   
    -moz-transition: all 0.3s ease 0s;
    -webkit-transition: all 0.3s ease 0s;
    -o-transition: all 0.3s ease 0s;
}
#nav{position:relative;z-index: 20;}
.nav{font-size: 18px;color: #ffffff;height: 50px;line-height:50px;background: #23498f;box-shadow:0 3px 6px 0 rgba(218, 218, 218, 0.8);}
.nav-list,.nav-list ul{position: relative;}
.nav-list li{float:left;padding:0 36px;}
.nav-list li a{display:block;color:#fff;text-decoration:none;
    transition: all 0.3s ease 0s;
    -ms-transition: all 0.3s ease 0s;   
    -moz-transition: all 0.3s ease 0s;
    -webkit-transition: all 0.3s ease 0s;
    -o-transition: all 0.3s ease 0s;}
.nav-list li.nav_a{background-color:#c71a25;color:#fff;}
.nav_a_hover{position: absolute;top:0;background-color:transparent;border-bottom:3px solid #c71a25;color:#fff;height:47px;}