/* Default: tampilkan desktop layout, sembunyikan mobile */
.desktop-only { display: block; }
.mobile-only { display: none; }

.timeline-split {
  display: flex;
  max-width: 1000px;
  margin: 2rem auto;
  gap: 2rem;
}

.timeline-years {
  flex: 1;
  display: flex;
  flex-direction: column;
  border-right: 2px solid #eee;
  padding-right: 1rem;
}

.year-btn {
  background: none;
  border: none;
  padding: 1rem;
  text-align: left;
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s;
  border-left: 3px solid transparent;
}
.year-btn:hover {
  background: #f8f9fa;
}
.year-btn.active {
  color: #0d6efd;
  border-left: 3px solid #0d6efd;
  background: #f1f5ff;
}

.timeline-description {
  flex: 3;
  padding: 1.5rem;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 3px 8px rgba(0,0,0,0.05);
  min-height: 200px;
}
.desc-item { display: none; }
.desc-item.active { display: block; }

/* Mobile Layout */
@media (max-width: 768px) {
  .desktop-only { display: none; }
  .mobile-only { display: block; }

  .timeline-split {
    display: block;
  }

  .timeline-mobile .mobile-item {
    background: #fff;
    margin-bottom: 1rem;
    padding: 1rem 1.2rem;
    border-radius: 10px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  }

  .timeline-mobile .mobile-item h3 {
    color: #0d6efd;
    margin-bottom: 0.5rem;
  }
}