/**导航*/
header{
    width: 100%;
    height: 80px;
    box-shadow: 1px 1px 8px #9d9d9d;
    position: sticky;
    z-index: 10;
    top: 0;
    background-color: white;
}
nav{
    height: 100%;
    margin: 0 auto;
    width: 1200px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    left: 0;
}
nav h1{
    background: url(../img/header-logo.jpg) no-repeat center center;
    background-size: 100%;
    width: 159px;
    height: 66px;
}
nav h1:hover{
    cursor: pointer;
}
nav ul{
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    list-style: none;
    position: relative;
}

nav ul li a{
    color: #333;
    font-size: 16px;
    height: 40px;
    width: 76px;
    font-weight: 600;
    letter-spacing: 2px;
}
nav ul li{
    border-radius: 6px;
    padding:0 20px;
    line-height: 40px;
    transition: all 1s;
    margin-left: 10px;
}
nav ul .home-active{
    background-color: #3f5796;
    color: white;
    border-radius: 6px;
}
nav ul li:hover{
    background-color: #3f5796;
    color: white;
}
nav ul li:hover a{
    color: white;
}
nav ul .case_item{
    position: relative;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 0;
}
nav ul .case_item dl dd a{
    color: #333;
    font-size: 16px;
}
nav ul .case_item dl dd a:hover{
    color: #3f5796;
}
nav ul li:nth-child(5){
    position: relative;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 0;
}
nav ul li:nth-child(5) dl dd a{
    color: #333;
    font-size: 16px;
}
nav ul li:nth-child(5) dl dd a:hover{
    color: #3f5796;
}
nav ul li:hover dl{
    background: white;
    color: #333;
    display: block;
    transition:all 0.5s
}
nav li dl{
    width: 160%;
    position: absolute;
    top: 40px;
    left: 0;
    padding: 0 2px 0 2px;
    transition: all 0.5s;
    display: none;
    border-radius: 6px;
}
nav li dl dd{
    width: 100%;
    height: 52px;
    margin-bottom: 0;
    line-height: 60px;
    border-bottom: 1px dotted #999;
}
nav li dl dd a{
    display: inline-block;
    width: 100%;
    height: 100%;
}
nav li dl dd:hover a{
    /* background: #3f5796; */
    color: white;
}
nav li dl dd:hover a{
    color: white;
}
/* nav ul li dl:hover{
    background: #3f5796;
    color: white;
} */
/* .blog_about{
    position: absolute;
    right: 76px;
    top: 80px;
    background: white;
    width: 76px;
    display: none;
}
.blog_about dl{
    width: 100%;

}
.blog_about dd{
    width: 100%;
    height: 56px;
    line-height: 56px;
    transition: all 0.5s;
    display: none;

}
.blog_about dd a{
    width: 100%;
    height: 100%;
    text-align: center;
    display: inline-block;
    font-size: 16px;
    letter-spacing: 1px;
    color: #333;
    transition: all 0.5s;
}
.blog_about a:hover {
    background: #3f5796;
    color: white;
    transition: all 0.5s;
}
.about_hideen:hover.blog_about dt{
    display: block;
} */