.title1{
    text-align: center;
    /* margin-left: 18%; */
    
    list-style: none;
    /* margin-left: 100px; */
    height: 75px;
}
.title1 .drop-down{
    text-align: center;
    float: left;
    width: 171.9px;
    height: 35px;
    
    margin-top: 30px;
    border: 3px solid wheat;
    margin-left: 10px;
    background-color: #7bae82;

    
}
.home{
    color: aliceblue;
    
}
.hov1{
    height: 100px;
    width: 100px;
    padding: 0;
    opacity: 1;
    display: block;
    height: 0;
    /* overflow: hidden;     */
    transition: all 1s ease;
    position: absolute;
    margin-left:171.9px ;
    background-color: #2f3e45;
    margin-top: 50px;
}
.hov2{
    height: 100px;
    width: 100px;
    padding: 0;
    opacity: 1;
    display: block;
    height: 0;
    /* overflow: hidden;     */
    transition: all 1s ease;
    position: absolute;
    margin-left:171.9px ;
    background-color: #2f3e45;
    margin-top: 100px;
}

.hov .net1{
    margin-left: 171.9px;
}
.hov .net2{
    margin-left: 343.8px;
}
.hov .net3{
    margin-left: 515.7px;
}
.hov1 .TF1{
    margin-left: 171.9px;
}
.hov2 .Erasers{
    margin-left: 171.9px;
}
.hov2 .Readers{
    margin-left: 343.8px;
}
.introduction{
    margin-left: 171.9px;
}
.Reference{
    margin-left: 171.9px;
}

.hov{
    height: 100px;
    width: 200px;
    padding: 0;
    opacity: 1;
    display: block;
    height: 0;
    /* overflow: hidden;     */
    transition: all 1s ease;
    position: absolute;
    margin-left:171.9px ;
    background-color: #2f3e45;
    float: left;
}
.hov2 li a:hover{
    opacity: 1;
    background-color: red;
}


.hov1 li a:hover{
    opacity: 1;
    background-color: red;
}
.hov li a:hover {
    opacity: 1;
    background-color: red;

}
.hov2 li a{
    display: block;
    text-decoration: none;
    width: 171.9px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    color: white;
    background-color: #2f3e45;
    background-size: over;
}
.hov1 li a{
    display: block;
    text-decoration: none;
    width: 171.9px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    color: white;
    background-color: #2f3e45;
    background-size: over;
}
.hov li a{
    /* display: block; */
    text-decoration: none;
    width: 171.9px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    color: white;
    background-color: #2f3e45;
    background-size: over;

}
.drop-down:hover{
    background-color: #9faa9c;
}
.drop-down-content li a{
    text-align: center;
    display: block;
    text-decoration: none;
    width: 171.9px;
    height: 50px;
    text-align: center;
    line-height: 50px;
    color: rgb(255, 255, 255);
    background-color: #2f3e45;
    float: left;
}
.drop-down-content1 li a{
    text-align: center;
    display: block;
    text-decoration: none;
    width: 171.9px;
    height: 50px;
    /* text-align: center; */
    line-height: 50px;
    color: white;
    background-color: #2f3e45;
    float: left;
}
.title1 li:first-child a{
    border-radius: 10px 10 10 10px;
}
.title1 li:last-child a{
    border-radius: 10 10px 10px 10;
}
.drop-down{
    text-align: center;
    /* position: relative; */
    height: 0px;
    
}
.drop-down a{
    color: #ffffff;
}
.drop-down-content{
    text-align: center;
    padding: 0;
    opacity: 0;
    height: 0;
    overflow: hidden;    
    transition: all 1s ease;
    /* position: absolute; */
    margin-top: 10px;
}
.drop-down-content1{
    text-align: center;
    padding: 0;
    opacity: 0;
    height: 0;
    overflow: hidden;    
    transition: all 1s ease;
    /* position: absolute; */
    margin-top: 10px;
}
.drop-down-content li a{
    text-align: center;
    font-size: 15px;
}
.drop-down-content1 li a{
    text-align: center;
    font-size: 15px;
}
h3{
    font-size: 30px;
    clear: both;
/*            position: relative;
    z-index: -1;*/
}
.drop-down-content li a:hover {
    background-color:red;
    position: relative;
    z-index: 1;
    
}
.drop-down-content1 li a:hover {
    background-color:red;
    position: relative;
    z-index: 1;
    
}
.title1 .drop-down:hover .drop-down-content{
    opacity: 1;
    height: 150px;
}
.title1 .drop-down:hover .drop-down-content1{
    opacity: 1;
    height: 250px;
}
.nav {
    
    
    text-align: center;
    display:inline-block;
    height: 100px;
    width: 1500px;
    margin: 0 auto;
    
    clear: both;
    /* margin: 0 0 0px 0; */
    font-family: "Georgia", Tahoma, Sans-Serif;
    font-size: 20px;
    font-weight: bold;
    display: block;
    
    
   
    
    
    

    
    
}
.zhongxin1{
    
}
.nav .nav1 {
    
    display:inline-block;
    text-align: center;
    
    
    /* position: absolute; */
    /* margin-top: 20px; */
    /* margin-bottom: 50px;*/
    /*background-color: #7bae82;*/
    
}