extra.less
CSS:
.structItemContainer-group--sticky .structItem-title:after {
content: 'Important';
font-size: 12px;
color: #fdfdfd;
background: #dd3d3d;
border-radius: 3px;
padding-top: 1px;
padding-right: 4px;
padding-bottom: 1px;
padding-left: 4px;
}