小编Lib*_*cob的帖子

.tree ul {
    margin-left: 20px;
}

.tree li {
    list-style-type: none;
    margin:15px;
    position: relative;
    cursor: pointer;
}

.tree li .submenuBtn{
    margin-left:8px;
    display: none;
    font-weight:bolder;
}

.tree li a:hover .submenuBtn{
    display: inline-block;
}

.tree li img::clicked + #contextMenu{
    display: inline-block;
}

.tree li::before {
    content: "";
    position: absolute;
    top:-7px;
    left:-20px;
    border-left: 1px solid #ccc;
    border-bottom:1px solid #ccc;
    border-radius:0 0 0 0px;
    width:20px;
    height:15px;
}

.tree li::after {
    position:absolute;
    content:"";
    top:8px;
    left:-20px;
    border-left: 1px solid #ccc;
    border-top:1px solid #ccc;
    border-radius:0px 0 …