treeview.css

/* the tree node's style */

.tree-view {

overflow-y: hidden;

}

.tree-view_item {

/* immediate child of .tree-view, for styling convenience */

}

/* style for the children nodes container */

.tree-view_children {

margin-left: 16px;

}

.tree-view_children-collapsed {

height: 0px;

}

.tree-view_arrow {

cursor: pointer;

margin-right: 6px;

display: inline-block;

-webkit-user-select: none;

-moz-user-select: none;

-ms-user-select: none;

user-select: none;

}

.tree-view_arrow:after {

content: '▾';

}

/* rotate the triangle to close it */

.tree-view_arrow-collapsed {

-webkit-transform: rotate(-90deg);

-moz-transform: rotate(-90deg);

-ms-transform: rotate(-90deg);

transform: rotate(-90deg);

}