tree.less

.tree {
  @node-height: 16px;
  overflow: auto;
  .node {
    width: 100%;
    .directory-level {
      position: relative;
      padding-right: 4px;
      white-space: nowrap;
      font-size: @node-height;
      line-height: @node-height;
      >.icon {
        height: @node-height;
      }
      .operation {
        display: inline;
        margin-left: 20px;
        visibility: hidden;
        img {
          height: @node-height;
        }
      }
      &:hover {
        .operation {
          visibility: visible;
        }
      }
    }
    .sub-node {
      padding-left: 14px;
    }
  }
}