body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  line-height: 1.6;
  background-color: #f4f4f4;
  color: #333;
  margin: 0;
  padding: 20px;
}
#timeline-container {
  max-width: 900px;
  margin: 0 auto;
  position: relative;
  padding: 20px 0;
}
#timeline-container::before {
  content: "";
  position: absolute;
  width: 4px;
  background-color: #007bff;
  left: 50%;
  top: 0;
  bottom: 0;
  margin-left: -2px;
}
.timeline-item {
  padding: 10px 40px;
  position: relative;
  background-color: inherit;
  width: 50%;
  box-sizing: border-box;
  cursor: pointer;
  transition: background-color 0.3s ease;
}
.timeline-item.left {
  left: 0;
  padding-right: 25px;
}
.timeline-item.right {
  left: 50%;
  padding-left: 25px;
}
.timeline-item::after {
  content: "";
  position: absolute;
  width: 25px;
  height: 25px;
  right: -13px;
  background-color: white;
  border: 4px solid #007bff;
  top: 15px;
  border-radius: 50%;
  z-index: 1;
  transition: background-color 0.3s ease;
}
.timeline-item.right::after {
  left: -13px;
}
.timeline-item:hover {
  background-color: #e9ecef;
}
.timeline-item:hover::after {
  background-color: #007bff;
}
.content {
  padding: 20px 30px;
  background-color: white;
  position: relative;
  border-radius: 6px;
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
}
.content h2 {
  margin-top: 0;
  color: #007bff;
}
.content p {
  margin: 0;
}
.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.6);
  padding-top: 60px;
}
.modal-content {
  background-color: #fefefe;
  margin: 5% auto;
  padding: 30px;
  border: 1px solid #888;
  width: 80%;
  max-width: 700px;
  border-radius: 8px;
  position: relative;
}
.close {
  color: #aaa;
  position: absolute;
  top: 10px;
  right: 25px;
  font-size: 35px;
  font-weight: bold;
}
.close:hover,
.close:focus {
  color: black;
  text-decoration: none;
  cursor: pointer;
}
h1 {
  text-align: center;
  color: #333;
  margin-bottom: 40px;
}

@media screen and (max-width: 768px) {
  #timeline-container::before {
    left: 31px;
  }
  .timeline-item {
    width: 100%;
    padding-left: 70px;
    padding-right: 25px;
  }
  .timeline-item.right {
    left: 0%;
  }
  .timeline-item::after {
    left: 18px;
  }
}