.event {
    position: absolute;
    width: 3px;
    height: 3px;
    border-radius: 150px;
    bottom: 3px;
    left: calc(50% - 1.5px);
    content: " ";
    display: block;
    background: #3d8eb9;
}

.event.busy {
    background: #f64747;
}