src/styles/components/tree.less

@tree-prefix-cls: ~"@{css-prefix}tree";
.@{tree-prefix-cls} {
    ul{
        list-style: none;
        margin: 0;
        padding: 0;
        font-size: @font-size-small;
        li{
            list-style: none;
            margin: 8px 0;
            padding: 0;
            white-space: nowrap;
            outline: none;
        }
    }
    li{
        ul{
            margin: 0;
            padding: 0 0 0 18px;
        }
    }
    &-title {
        display: inline-block;
        margin: 0;
        padding: 0 4px;
        border-radius: @btn-border-radius-small;
        cursor: pointer;
        vertical-align: top;
        color: @text-color;
        transition: all @transition-time @ease-in-out;
        &:hover {
            background-color: tint(@primary-color, 90%);
        }
        &-selected, &-selected:hover{
            background-color: tint(@primary-color, 80%);
        }
    }
    &-arrow{
        cursor: pointer;
        width: 12px;
        text-align: center;
        display: inline-block;
        i {
            transition: all @transition-time @ease-in-out;
        }
        &-open{
            i {
                transform: rotate(90deg);
            }
        }
        &-hidden{
            cursor: auto;
            i{
                display: none;
            }
        }
        &-disabled{
            cursor: @cursor-disabled;
        }
    }
}