/* スマホ：縦に並ぶ基本レイアウト */
.timeline {
  position: relative;
  margin-left: 2rem;
  border-left: 2px solid #ccc;
  padding-left: 1rem;
}

.timeline-item {
  position: relative;
  margin-block: 2rem;
}

.timeline-date {
  font-weight: bold;
  color: #555;
}

.timeline-content {
  margin-top: 0.5rem;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -1.2rem;
  top: 0.25rem;
  width: 12px;
  height: 12px;
  background: #fff;
  border: 2px solid #666;
  border-radius: 50%;
}


/* PC：左右に交互配置 */
@media (min-width: 768px) {
  .timeline {
    position: relative;
    padding-left: 0;
    border-left: none;
  }

  .timeline::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 50%;
    width: 2px;
    background: #ccc;
  }

  .timeline-item {
    width: 50%;
    padding: 1rem 2rem;
    box-sizing: border-box;
    position: relative;
  }

  .timeline-item:nth-child(odd) {
    left: 0;
    text-align: right;
  }

  .timeline-item:nth-child(even) {
    left: 50%;
    text-align: left;
  }

  .timeline-item::before {
    top: 1rem;
    left: auto;
    right: -0.6rem;
  }

  .timeline-item:nth-child(even)::before {
    left: -0.4rem;
    right: auto;
  }
}