/* 发展历程 */
.content{
    max-width: 12rem;
    margin: 0 auto;
    padding:2rem 0 1rem 0;
    box-sizing: border-box;
}
.content ul li{
    line-height: .32rem;
    color: rgba(51, 51, 51, 1);
    font-size: .18rem;
    border-right: .01rem dashed red;
    text-align:right;
    width: 50%;
    display: block;
    padding: 0 .5rem .2rem 0;
    box-sizing: border-box;
    position: relative;
    left: 0;
    top: 0;
}

.content ul li:nth-child(odd){
    border-left: .01rem dashed red;
    text-align:left;
    margin-left: 49.9%;
    border-right: none;
  
}
.content ul li:nth-child(odd) p{
    padding: 0 0 0 .5rem;
    box-sizing: border-box;
}
.content ul li p.date{
    color: #D51A34;
}
.content ul li::before{
    width: .5rem;
    height: .16rem;
    background-image: url(../img/course/icon.png);
    background-repeat: no-repeat;
    content: ""; 
    position: absolute; 
    left: -.08rem;
    top: 1.16rem;
    background-size: contain;
}
.content ul li:nth-child(even)::before{
    left:5.58rem;
     -webkit-transform: rotate(180deg); 
    -moz-transform: rotate(180deg); 
    -ms-transform: rotate(180deg); 
    -o-transform: rotate(180deg); 
    transform: rotate(180deg); 
}
/* 年 */
.content ul li.year{
    padding-top:1rem;
    box-sizing: border-box;
}

.content ul li.year::before{
    top: 2.15rem;
}
.content ul li.year_2020{
    padding-top: 0;
}
.content ul li.year_2020::before{
    top: 1.16rem;
}
.year b{
    background-image: url(../img/course/year.png);
    width: 1.08rem;
    height: 1.08rem;
    background-repeat: no-repeat;
    position: relative; 
    left: -.55rem;
    top: -.8rem;
    display: block; 
    text-align: center;
    line-height: 1.08rem;
    color: rgba(255, 255, 255, 1);
    font-size: .16rem;
    background-size: contain;
}
.content ul li.years b{
    left: 5.45rem;
}
.content ul li.none_year::before{
    top: .06rem;
}