Styling… Almost got it but not quite right

Hi, I have got my calendars linked and managed to get background styling to apply to each one but it isn’t quite what I would like.

I really want to just colour the balls not the entire box, is this possible please?

This is what I have and my CSS, i am very new to WordPress

/* Color for Session 1 (pgcal-event-0) */
.pgcal-event-0 {
    background-color: green;
}

/* Color for Session 2 (pgcal-event-1) */
.pgcal-event-1 {
    background-color: red;
}

/* Color for Session 3 (pgcal-event-2) */
.pgcal-event-2 {
    background-color: blue;
}

/* Color for Session 4 (pgcal-event-3) */
.pgcal-event-3 {
    background-color: yellow;
}

/* Color for Session 5 (pgcal-event-4) */
.pgcal-event-4 {
    background-color: brown;
}

/* Color for Session 6 (pgcal-event-5) */
.pgcal-event-5 {
    background-color: purple;
}