.timeline{
  /* From the 2020 tutorial with its custom colors */
  --uiTimelineMainColor: var(--timelineMainColor, #222);
  --uiTimelineSecondaryColor: var(--timelineSecondaryColor, #fff);

  /* --uiTimelineMainColor: var(--timelineMainColor, #ff0068); */

  position: relative;
  padding-top: 0rem;
  padding-bottom: 1rem;
  margin-bottom: 2rem;

  /* From the 2020 tutorial */
  /* --timelineMainColor: #4557bb; */
  /* Waabi 2021-06 box background color */
  --timelineMainColor: #040b21;
  font-size: 16px;
}

.timeline:before{
  content: "";
  width: 4px;
  height: 100%;
  background-color: var(--uiTimelineMainColor);

  position: absolute;
  top: 0;
}

.timeline__group{
  position: relative;
}

.timeline__group:not(:first-of-type){
  margin-top: 2rem;
}

.timeline__year{
  padding: .5rem 1.5rem;
  color: var(--uiTimelineSecondaryColor);
  background-color: var(--uiTimelineMainColor);

  /* position: absolute; */
  margin-bottom: 1rem;
  left: 0;
  top: 0;
}

.timeline__box{
  position: relative;
}

.timeline__box:not(:last-of-type){
  margin-bottom: 24px;
}

.timeline__box:before{
  content: "";
  width: 100%;
  height: 2px;
  background-color: var(--uiTimelineMainColor);

  position: absolute;
  top: 32px;
  left: 0;
  z-index: -1;
}

.timeline__date{
  width: 90px;
  position: absolute;
  top: 0;
  left: 0;
  line-height: 1.0;

  box-sizing: border-box;
  padding: .5rem 0.0rem;
  text-align: center;

  background-color: var(--uiTimelineMainColor);
  color: var(--uiTimelineSecondaryColor);
}

.timeline__day{
  font-weight: 700;
  display: block;
}

.timeline__month{
  display: block;
  font-size: .8em;
  text-transform: uppercase;
}

.timeline__post{
  /* padding: 1.5rem 2rem; */
  padding: 0.75rem 1rem;
  border-radius: 2px;
  border-left: 3px solid var(--uiTimelineMainColor);
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, .12), 0 1px 2px 0 rgba(0, 0, 0, .24);
  background-color: var(--uiTimelineSecondaryColor);
}

/* Waabi: Make session titles a bit bolder to match the waabi style. */
.timeline__post .display-4 {
  font-family: "Poppins";
  font-weight: 700;
  margin-bottom: 0;
}

.timeline__content .card-body {
  margin-top: 0.5rem;
}

@media screen and (min-width: 641px){

  .timeline:before{
    left: 30px;
  }

  .timeline__group{
    padding-top: 30px;
  }

  .timeline__box{
    padding-left: 120px;
  }

  .timeline__box:before{
    top: 20px;
    transform: translateY(-50%);
  }

  .timeline__date{
    top: 32px;
    margin-top: -27px;
  }
}

@media screen and (max-width: 640px){

  .timeline:before{
    left: 0;
  }

  .timeline__group{
    padding-top: 30px;
  }

  .timeline__box{
    padding-left: 20px;
    padding-top: 70px;
  }

  .timeline__box:before{
    top: 90px;
  }

  .timeline__date{
    top: 0;
  }
}