.tribe-mini-calendar .tribe-events-has-events div[id*='daynum-'] a:before {
    content: '';
    display: block;
    height: 7px;
    width: 7px;
    padding: 0;
    background: red !important;
    margin: 5px auto 0 -4px;
    position: absolute;
    left: 50%;
    bottom: 4px;
    border-radius: 7px;
    -moz-border-radius: 7px;
    -webkit-border-radius: 7px;
}