main{
    user-select: none;
}
main > ul:last-of-type{
    width: 1300px;
    /* height: 1060px; */
    margin: auto;
    /* background-color: aqua; */
}
main > ul:last-of-type > li{
    width: 1300px;
    /* height: 490px; */
    /* background-color: azure; */
}
main > ul:last-of-type > li:last-of-type{
    margin-top: 80px;
}
main > ul:last-of-type > li:first-of-type > ul{
    display: flex;/*弹性盒模型*/
    justify-content: space-between;/* 主轴两侧对齐 */
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type{
    width: 870px;
    /* height: 490px; */
    /* background-color: bisque; */
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul{
    position: relative;/*相对定位*/
    display: flex;/*弹性盒模型*/
    justify-content: space-between;/* 主轴两侧对齐 */
}
/* main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li{
    /* height: 490px; *
    /* background-color: blueviolet; *
} */
/* 导航 */
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li{
    width: 125px;
    background-color: rgb(255, 238, 0);
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li > ul > li:first-of-type:hover{
    cursor: pointer;/*小手*/
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type{
    width: 125px;
    color: rgb(250, 250, 250);
    background-color: rgb(0, 98, 255);
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li > ul > li:first-of-type > p{
    width: 95px;
    height: 68.5px;
    font-size:20px;/*字体大小*/
    font-weight:bold;/*字体粗细*/
    line-height:68px;/*字体垂直居中*/
    text-align:center;/*字体水平居中*/
    /* background-color: burlywood; */
}
/* 杠杠 */
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li > ul{
    position: relative;/*相对定位*/
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li > ul > li:last-of-type{
    display: none;
    position: absolute;/* 绝对定位 */
    top: 7px;
    left: 95px;
    z-index:1;/* 定位层级 */
    width: 100px;
    height: 55px;
    background-color: rgb(210, 105, 30);
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li:first-of-type > ul > li:last-of-type{
    display: block;
}
/*main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:nth-child(2) > ul{
    display: flex;/*弹性盒模型*
    width: 100px;
    height: 490px;
    flex-wrap: wrap;/*弹性换行*
    justify-content: center;/* 主轴居中 *
    align-content: space-around;/* 两侧有相同间距 *
    /* background-color: cornflowerblue; *
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:nth-child(2) > ul > li:first-of-type{
    background-color: chocolate;
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:nth-child(2) > ul > li{
    width: 100px;
    height: 55px;
    background-color: transparent;
    z-index:1;/* 定位层级 *
} */
/* 平面内容 */
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:last-of-type{
    width: 710px;
    background-color: darkkhaki;
}
/* main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:last-of-type > ul{
    position: relative;/*相对定位*
} */
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:last-of-type > ul > li{
    display: none;
    position: absolute;/* 绝对定位 */
    width: 710px;
    height: 480px;
    text-align:center;/*字体水平居中*/
    /* background-color: chartreuse; */
}
main > ul:last-of-type > li:first-of-type > ul > li:first-of-type > ul > li:last-of-type > ul > li:first-of-type{
    display: block;
}
/* 标题 */
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:first-of-type{
    height: 160px;
}
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:first-of-type > P{
    width: 400px;
    height: 0px;
    margin: auto;
    font-size:60px;/*字体大小*/
    font-weight:bold;/*字体粗细*/
    line-height:160px;/*字体垂直居中*/
    text-align:center;/*字体水平居中*/
    /* background-color: brown; */
}
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:first-of-type > P:hover{
    color: rgb(117, 0, 138);
}
/* 知识 */
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:nth-child(2){
    position: relative;/*相对定位*/
    width: 400px;
    height: 320px;
    background-color: rgb(240, 240, 240);
}
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:nth-child(2) > p{
    display: none;
    position: absolute;/* 绝对定位 */
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    width: 288px;
    height: 270px;
    margin: auto;
    font-size:18px;/*字体大小*/
    color: rgb(2, 0, 34);
    text-indent: 35px;  /*文本缩进*/
}
main > ul:last-of-type > li:first-of-type > ul > li:nth-child(2) > ul > li:nth-child(2) > p:first-of-type{
    display: block;
}
main > ul:last-of-type > li:first-of-type > ul > li:last-of-type{
    width: 400px;
    /* height: 490px;
    background-color: bisque; */
}
main > ul:last-of-type > li:last-of-type > ul{
    display: flex;/*弹性盒模型*/
    justify-content: space-between;/* 主轴两侧对齐 */
}
/* main > ul:last-of-type > li:last-of-type > ul > li:first-of-type{
    background-color: lightgreen;
} */
main > ul:last-of-type > li:last-of-type > ul > li:first-of-type > p{
    width: 138px;
    height: 80px;
    margin: 60px auto;
    font-size:100px;/*字体大小*/
    font-weight:bold;/*字体粗细*/
    line-height:77px;/*字体垂直居中*/
    text-align:center;/*字体水平居中*/
    /* background-color: rgb(146, 144, 238); */
}
main > ul:last-of-type > li:last-of-type > ul > li:first-of-type > p:hover{
    color: rgb(17, 0, 255);
}
main > ul:last-of-type > li:last-of-type > ul > li:first-of-type > section{
    width: 400px;
    height: 300px;
    background-color: rgb(81, 155, 155);
}
main > ul:last-of-type > li:last-of-type > ul > li:last-of-type{
    width: 720px;
    height: 540px;
    background-color: darkcyan;
}