*{
    margin: 0;
    padding: 0;
}
a{
    text-decoration: none;
}
li{
    list-style: none;
}
.header_top{
    width: 100%;
    height: 187px;
    background: url(../images/header-top.png) no-repeat;
    background-size: 100% 100%;
}
.header_img{
    width: 1200px;
    height: 70px;
    margin: 0 auto;
    padding-top: 29px;
    display: flex;
    align-items: center;
}
.header_logo{
    width: 1200px;
    height: 50px;
    margin: 0 auto;
    padding-top: 20px;
}
nav{
    width: 100%;
    height: 72px;
    background-color: #2553A3;
    position: relative;
}
nav .nav{
    width: 1200px;
    height: 72px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
nav .nav ul li{
    float: left;
    font-size: 24px;
    height: 72px;
    line-height: 72px;
}
nav .nav ul li a{
    color: #fff;
    padding: 0 63px;
    position: relative;
}
nav .nav ul li a::after{
    content: '';
    position: absolute;
    background-color: #fff;
    width: 1px;
    height: 24px;
    top: 5px;
    right: 0;
}
nav .nav ul li:last-child a::after{
    content: none;
}
.search{
    float: right;
    position: relative;
}
.search input{
    width: 248px;
    height: 48px;
    border-radius: 24px;
    border: none;
    outline: none;
    font-size: 16px;
    padding-left: 17px;
    padding-right: 115px;
}
.search a{
    position: absolute;
    right: 6px;
    top: 5px;
    background: #2553A3;
    border-radius: 19px;
    display: inline-block;
    width: 96px;
    height: 39px;
    color: #fff;
    text-align: center;
    line-height: 39px;
    font-size: 20px;
    font-weight: bold;
}

/* 下拉列表 */
.xiala_bg{
    width: 100%;
    height: 420px;
    background:url(../images/nav_bg.png) no-repeat;
    background-size:100% 100%;
    border-top: 1px solid #2B88DD;
    position: absolute;
    left: 0;
    top: 72px;
    display: none;
    z-index: 99;
}
.xiala{
    width: 1200px;
    margin: 0 auto;
    position: relative;
}
.xiala_bg .xiala1 .ul{
    position: absolute;
    top: 34px;
    left: 220px;
}
.xiala_bg .xiala2 .ul{
    position: absolute;
    top: 34px;
    left: 420px;
}
.xiala_bg .xiala3 .ul{
    position: absolute;
    top: 34px;
    left: 640px;
}
.xiala_bg .xiala .ul a{
    color: #D6E5FE;
    padding-left: 16px;
    font-size: 18px;
    line-height: 42px;
    display: block;
}
.xiala_bg .xiala .ul a:hover{
    font-weight: bold;
    background: url(../images/xiaojiantou.png) no-repeat 0 center;
}
.xiala_bg .xiala .ul a::after{
    content: none;
}