.timeline-item::before {
    content: "";
    position: absolute;
    left: -7px;
    top: 6px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: #bbb; /* padrão */
}

.timeline-item.tl-success::before {
    background-color: #28a745 !important;
}

.timeline-item.tl-danger::before {
    background-color: #dc3545 !important;
}

.timeline-item.tl-info::before {
    background-color: #17a2b8 !important;
}