@import url("https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/twitter-bootstrap/5.0.0-alpha1/css/bootstrap.min.css");
.tree {
min-height:20px;
padding:19px;
margin-bottom:20px;
background-color:#fbfbfb;
border:1px solid #999;
-webkit-border-radius:4px;
-moz-border-radius:4px;
border-radius:4px;
-webkit-box-shadow:inset 0 1px 1px rgba(0,0,0,0.05);
-moz-box-shadow:inset 0 1px 1px rgba(0,0,0,0.05);
box-shadow:inset 0 1px 1px rgba(0,0,0,0.05)
}
.tree li {
list-style-type:none;
margin:0;
padding:10px 5px 0 5px;
position:relative
}
.tree li::before,.tree li::after {
content:'';
left:-20px;
position:absolute;
right:auto
}
.tree li::before {
border-left:1px solid #999;
bottom:50px;
height:100%;
top:0;
width:1px
}
.tree li::after {
border-top:1px solid #999;
height:20px;
top:25px;
width:25px
}
.tree li div {
-moz-border-radius:5px;
-webkit-border-radius:5px;
border:1px solid #999;
border-radius:5px;
display:inline-block;
padding:3px 8px;
text-decoration:none;
max-width:200px;
cursor:pointer
}
.tree>ul>li::before,.tree>ul>li::after {
border:0
}
.tree li:last-child::before {
height:30px
}
.tree li.parent_li>div:hover,.tree li.parent_li>div:hover+ul li div {
background:#eee;
border:1px solid #94a0b4;
color:#000
}
需要引用bootstrap.min.css,展开收缩的图标可以换成自己的