styles.css

.block_groups div.memberlist {
    list-style: url('[[pix:i/navigationitem]]');
}

.block_groups input.blockgroupsandgroupingcheckbox {
    cursor: pointer;
    display: none;
    text-align: left;
}

.block_groups input.blockgroupsandgroupingcheckbox ~ label::before {
    content: url('[[pix:t/collapsed]]');
}

.block_groups input.blockgroupsandgroupingcheckbox:checked ~ label::before {
    content: url('[[pix:t/expanded]]');
}

.block_groups input.blockgroupsandgroupingcheckbox ~ ul {
    display: none;
}

.block_groups input.blockgroupsandgroupingcheckbox:checked ~ ul {
    display: block;
    list-style: url('[[pix:i/navigationitem]]');
    padding-left: 16px;
}

.block_groups .rightalign {
    float: right;
}

.block_groups .hiddengroups {
    opacity: 0.5;
}
.block_groups img {
    margin-right: 5px;
    margin-top: 3px;
    vertical-align: top;
}
.block_groups li {
    line-height: 22px;
}
.block_groups .block-groups-warning,
.block_groups .block-groups-spinner {
    padding-right: 6px;
}