chrome/browser/resources/file_manager/foreground/css/tree.css

/* Copyright 2013 The Chromium Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file. */

/* Derived from /ui/webui/resources/css/table.css. */

tree {
  display: block;
  outline: none;
  overflow: auto;
}

.tree-item > .tree-row {
  -webkit-user-select: none;
  cursor: default;
  position: relative;
  white-space: nowrap;
}

.expand-icon {
  -webkit-transform: rotate(-90deg);
  -webkit-transition: all 150ms;
  background-image: -webkit-canvas(tree-triangle);
  background-position: 50% 50%;
  background-repeat: no-repeat;
  background-size: 8px 5px;
  display: inline-block;
  height: 16px;
  position: relative;
  vertical-align: top;
}

html[dir=rtl] .expand-icon {
  -webkit-transform: rotate(90deg);
}

.tree-item[expanded] > .tree-row > .expand-icon {
  -webkit-transform: rotate(0);
  background-image: -webkit-canvas(tree-triangle);
}

.tree-row .expand-icon {
  visibility: hidden;
}

.tree-row[may-have-children] .expand-icon {
  visibility: visible;
}

.tree-row[has-children=false] .expand-icon {
  visibility: hidden;
}

.tree-row[selected] {
  z-index: 2;
}

.tree-children[expanded] {
  display: block;
}

.tree-children {
  display: none;
}

.tree-item > .tree-row > * {
  display: inline-block;
}

.tree-label {
  white-space: pre;
}

/* We need to ensure that even empty labels take up space */
.tree-label:empty::after {
  content: ' ';
  white-space: pre;
}

.tree-rename > .tree-row > .tree-label {
  -webkit-user-modify: read-write-plaintext-only;
  -webkit-user-select: auto;
}