.content{
    width: 1200px;
    margin:0  auto;
}
.convention-box{
    width: 100%;
}
.convention-ch{
    font-size: 30px;
    font-weight: bold;
    color: #333333;
}
.convention-en{
    font-size: 20px;
    color: #999999;
    margin-top: 14px;
    line-height: 32px;
}
.introduce{
    font-size: 24px;
    color: #333333;
    line-height: 48px;
    margin-top: 32px;
    display: block;
    letter-spacing: 2px;
}
.session-unkown{
   height: 310px;
   background-color: #000; 
   display: flex;
   flex-direction: column;
   /* justify-content: space-around; */
   align-items: center;
   padding-top: 57px;
   margin: auto;
}
.session-unkown .title{
    color: #ffffff;
    font-size: 34px;
    letter-spacing: 10px;
    font-weight: 400;
}
.session-unkown .underline{
    width: 70px;
    height: 1px;
    background-color: #f5f5f5;
    margin-top: 16px;
}
.session-unkown .descibe{
    color: #ffffff;
    margin-top: 48px;
    font-size: 22px;
    line-height: 36px;
    letter-spacing: 4px;
    opacity: 0.8;
}
.articletitle{
    display: flex;
    margin: auto;
    padding-bottom: 20px;
}
.articletitle ul{
    width: 33.33%;
    border-left: 1px solid #333333;
    padding: 0 55px ;
}
.articletitle ul:first-child{
    border:none
}
.articletitle ul li{
    border-bottom: 1px solid #333333;
    line-height: 61px;
    font-size: 18px;
}
.articletitle ul li:first-child{
    font-size: 26px;
    font-weight: 600;
    line-height: 80px;
}
.articletitle ul li:last-child{
    border: none;
}
.area{
    font-size: 22px;
    opacity: 0.8;
    font-weight: normal;
    margin-top: 30px;
}
.imglist{
    position: relative;
    width: 100%;
    height: 900px;
}
.session1{
    width: 690px;
    height: 300px;
    border-radius: 0px 0px 0px 0px;
    opacity: 0.4;
    border: 3px solid #000000;
    position: absolute;
    left: 0;
    top: 165px;
    z-index: 2;
}
.session2{
    width: 690px;
    height: 300px;
    background: url(../images/about_2.png) center no-repeat;
    background-size: 100% 100%;
    border: 5px solid #fff;
    position: absolute;
    left: 40px;
    top: 205px;
    z-index: 3;
    transition: all 0.3s;

}
.session2:hover,.session4:hover,.session5:hover{
    z-index: 6;
    transform: scale(1.1);
}
.session3{
    width: 487px;
    height: 300px;
    opacity: 0.4;
    border: 4px solid #000000;
    position: absolute;
    top: 535px;
    left: 220px;
}
.session4{
    width: 487px;
    height: 300px;
    border: 6px solid #FFFFFF;
    position: absolute;
    top: 501px;
    left: 244px;
    background: url(../images/about_1.png) center no-repeat;
    z-index: 4;
    background-size: 100% 100%;
    transition: all 0.3s;

}
.session5{
    width: 500px;
    height: 700px;
    position: absolute;
    top: 100px;
    left: 730px;
    z-index: 5;
    background: url(../images/about_3.png) center no-repeat;
    background-size: 100% 100%;
    border: 6px solid #FFFFFF;
    transition: all 0.3s;

}