.collapsibleTableContainer .collapsibleTable-expander {
    cursor: pointer;
    display: inline-block;
    width: 16px;
    height: 16px;
    overflow: hidden;
    vertical-align: middle;
    background: var(--itemCollapsed, url("../images/itemCollapsed.png")) no-repeat 0px 0px;
    background-position-x: center;
    background-position-y: center;
    background-size: 70%;
}

    .collapsibleTableContainer .collapsibleTable-expander.expanded {
        background: url("../images/itemExpanded.png") no-repeat 0px 0px; /*[ url({itemExpanded}) no-repeat 0px 0px]*/
        background: var(--itemExpanded, url("../images/itemExpanded.png")) no-repeat 0px 0px;
        background-position-x: center;
        background-position-y: center;
        background-size: 60%;
    }