/* ============ SPINE TIMELINE ============ */
.spine-container {
  position: relative;
  width: 100%;
  max-width: 900px;
  margin: 5rem auto 2rem;
  padding: 2rem 0;
}

.spine-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: rgba(255, 255, 255, 0.15);
  transform: translateX(-50%);
  z-index: 1;
}

.spine-item {
  position: relative;
  width: 100%;
  display: flex;
  margin-bottom: 120px;
}

.spine-item:last-child {
  margin-bottom: 0;
}

.spine-dot {
  position: absolute;
  left: 50%;
  top: 0.43rem;
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
  transform: translate(-50%, -50%) scale(0);
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  z-index: 2;
  box-shadow: 0 0 10px rgba(165, 243, 161, 0.5);
}

.spine-content {
  width: 50%;
  display: flex;
  flex-direction: column;
  position: relative;
}

.spine-content::after {
  content: '';
  position: absolute;
  top: 0.43rem;
  height: 1px;
  background: rgba(255, 255, 255, 0.15);
  z-index: 1;
  transition: opacity 0.45s ease-out, transform 0.45s ease-out;
}

.spine-category {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--fg-3);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  line-height: 1.2;
}

.spine-value {
  font-size: clamp(2rem, 3.5vw, 2.5rem);
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin: 0.5rem 0 0.85rem;
  color: white;
}

.spine-desc {
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--fg-2);
  max-width: 320px;
}

.spine-item-left {
  justify-content: flex-start;
  text-align: right;
}

.spine-item-left .spine-content {
  padding-right: 5.2rem;
  padding-left: 0;
  align-items: flex-end;
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity 0.45s ease-out, transform 0.45s ease-out;
}

.spine-item-left .spine-content::after {
  right: 0;
  left: auto;
  width: 4rem;
}

.spine-item-right {
  justify-content: flex-end;
  text-align: left;
}

.spine-item-right .spine-content {
  padding-left: 5.2rem;
  padding-right: 0;
  align-items: flex-start;
  opacity: 0;
  transform: translateX(30px);
  transition: opacity 0.45s ease-out, transform 0.45s ease-out;
}

.spine-item-right .spine-content::after {
  left: 0;
  right: auto;
  width: 4rem;
}

.spine-item.visible .spine-content {
  opacity: 1;
  transform: translateX(0);
}

.spine-item.visible .spine-dot {
  transform: translate(-50%, -50%) scale(1);
}

@media (max-width: 768px) {
  .spine-container {
    margin-top: 3rem;
    padding: 1rem 0;
  }
  .spine-line {
    left: 15px;
    transform: none;
  }
  .spine-item {
    margin-bottom: 60px;
    justify-content: flex-start !important;
    text-align: left !important;
  }
  .spine-content {
    width: 100% !important;
    padding-left: 4.25rem !important;
    padding-right: 0 !important;
    align-items: flex-start !important;
  }
  .spine-item-left .spine-content::after,
  .spine-item-right .spine-content::after {
    left: 13px !important;
    right: auto !important;
    width: 2.25rem !important;
    top: 0.43rem !important;
  }
  .spine-dot {
    left: 15px !important;
    top: 0.43rem !important;
  }
  .spine-desc {
    max-width: 100%;
  }
  .spine-item-left .spine-content {
    transform: translateX(30px);
  }
}