.floating-toc {
  position: fixed;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 260px;
  max-height: 70vh;
  background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-left: none;
  border-radius: 0 12px 12px 0;
  box-shadow: 4px 2px 20px rgba(0, 0, 0, 0.12), 0 0 0 1px rgba(255, 255, 255, 0.8) inset;
  z-index: 9999;
  opacity: 0;
  visibility: hidden;
  transform: translateX(-100%) translateY(-50%);
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.35s cubic-bezier(0.4, 0, 0.2, 1),
              visibility 0.3s;
  overflow: hidden;
}

.floating-toc.visible {
  opacity: 1;
  visibility: visible;
  transform: translateX(0) translateY(-50%);
}

.floating-toc-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px 10px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  background: linear-gradient(180deg, rgba(37, 131, 173, 0.04) 0%, transparent 100%);
}

.floating-toc-title {
  font-size: 14px;
  font-weight: 600;
  color: #2583ad;
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.floating-toc-title::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 14px;
  background: linear-gradient(180deg, #2583ad 0%, #1a6a8f 100%);
  border-radius: 2px;
}

.floating-toc-close {
  width: 24px;
  height: 24px;
  border: none;
  background: rgba(0, 0, 0, 0.04);
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #666;
  font-size: 14px;
  transition: all 0.2s ease;
}

.floating-toc-close:hover {
  background: rgba(0, 0, 0, 0.08);
  color: #333;
}

.floating-toc-content {
  padding: 12px 8px;
  max-height: calc(70vh - 50px);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(37, 131, 173, 0.3) transparent;
}

.floating-toc-content::-webkit-scrollbar {
  width: 4px;
}

.floating-toc-content::-webkit-scrollbar-track {
  background: transparent;
}

.floating-toc-content::-webkit-scrollbar-thumb {
  background: rgba(37, 131, 173, 0.3);
  border-radius: 2px;
}

.floating-toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.floating-toc-list li {
  position: relative;
  margin: 2px 0;
}

.floating-toc-list a {
  display: block;
  padding: 6px 12px;
  font-size: 13px;
  color: #555;
  text-decoration: none;
  border-radius: 6px;
  transition: all 0.2s ease;
  border-left: 2px solid transparent;
  line-height: 1.4;
}

.floating-toc-list a:hover {
  background: rgba(37, 131, 173, 0.08);
  color: #2583ad;
  border-left-color: #2583ad;
}

.floating-toc-list a.active {
  background: rgba(37, 131, 173, 0.12);
  color: #1a6a8f;
  border-left-color: #2583ad;
  font-weight: 500;
}

.floating-toc-list .toc-h2 {
  padding-left: 12px;
  font-size: 13px;
}

.floating-toc-list .toc-h3 {
  padding-left: 24px;
  font-size: 12px;
  color: #777;
}

.floating-toc-list .toc-h4 {
  padding-left: 36px;
  font-size: 11px;
  color: #888;
}

.floating-toc-hint {
  position: fixed;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 8px;
  height: 80px;
  background: linear-gradient(90deg, rgba(37, 131, 173, 0.15) 0%, transparent 100%);
  border-radius: 0 4px 4px 0;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 9998;
}

.floating-toc-hint.visible {
  opacity: 1;
  visibility: visible;
}

.floating-toc-hint:hover {
  width: 12px;
  background: linear-gradient(90deg, rgba(37, 131, 173, 0.35) 0%, transparent 100%);
}

@media screen and (max-width: 768px) {
  .floating-toc {
    width: 220px;
    max-height: 60vh;
  }

  .floating-toc-hint {
    display: none;
  }
}

@keyframes tocPulse {
  0%, 100% {
    opacity: 0.6;
  }
  50% {
    opacity: 1;
  }
}

.floating-toc-hint.has-toc {
  animation: tocPulse 2s ease-in-out infinite;
}