styles.css

.block_settings .block_tree ul {
    margin-left: 18px;
}

.block_settings .block_tree p.hasicon {
    text-indent: -21px;
    padding-left: 21px;
}

.block_settings .block_tree p.hasicon img {
    width: 16px;
    height: 16px;
    margin-top: 3px;
    margin-right: 5px;
    vertical-align: top;
}

.block_settings .block_tree p.hasicon.visibleifjs {
    display: block;
}

.block_settings .block_tree .tree_item.branch {
    padding-left: 21px;
}

.block_settings .block_tree .tree_item {
    cursor: pointer;
    margin: 3px 0;
    background-position: 0 50%;
    background-repeat: no-repeat;
}

.block_settings .block_tree .active_tree_node {
    font-weight: bold;
}

.block_settings .block_tree [aria-expanded="true"] {
    background-image: url('[[pix:t/expanded]]');
}

.block_settings .block_tree [aria-expanded="false"] {
    background-image: url('[[pix:t/collapsed]]');
}

.block_settings .block_tree [aria-expanded="true"].emptybranch {
    background-image: url('[[pix:t/collapsed_empty]]');
}

.block_settings .block_tree [aria-expanded="false"].loading {
    background-image: url('[[pix:i/loading_small]]');
}
/*rtl:raw:
.block_settings .block_tree [aria-expanded="false"] {background-image: url('[[pix:t/collapsed_rtl]]');}
.block_settings .block_tree [aria-expanded="true"].emptybranch {background-image: url('[[pix:t/collapsed_empty_rtl]]');}
.block_settings .block_tree [aria-expanded="false"].loading {background-image: url('[[pix:i/loading_small]]');}
*/
.block_settings .block_tree [aria-hidden="false"] {
    display: block;
}

.block_settings .block_tree  [aria-hidden="true"]:not(.icon) {
    display: none;
}