.gantt-task-group {
    position: absolute;

    background: rgb(99, 136, 205);

    height: 30%;

    top: -25%;
    bottom: 0;
    margin: auto;
}

.gantt-task-group-left-main,
.gantt-task-group-right-main {
    position: absolute;

    width: 12px;
    height: 100%;
    background: rgb(99, 136, 205);

    top: 0;
    bottom: 0;
    margin: auto 0;
}

.gantt-task-group-left-main {
    left: -6px;
}

.gantt-task-group-right-main {
    right: -6px;
}

.gantt-task-group-left-symbol,
.gantt-task-group-right-symbol {
    position: absolute;

    width: 0;
    height: 50%;

    top: 75%;
    bottom: 0;

    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-top: 12px solid rgb(99, 136, 205);
}

.gantt-task-group-left-symbol {
    left: -6px;
}

.gantt-task-group-right-symbol {
    right: -6px;
}

.gantt-task-overview {
    height: 40%;
    top: 40%;
    -webkit-filter: grayscale(0.6);
    filter: grayscale(0.6);
}

.gantt-task-overview .gantt-task-content {
    display: none;
}