* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  line-height: 1.6;
  color: #333;
  min-height: 100vh;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background-color: #2c3e50;
  color: white;
  padding: 2rem 0;
  position: relative;
  overflow: hidden;
}

header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(52, 152, 219, 0.1) 0%, rgba(155, 89, 182, 0.1) 100%);
}

.header-content {
  position: relative;
  z-index: 2;
  text-align: center;
}

.nav-links {
  margin-top: 1.5rem;
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.nav-link {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: 25px;
  background: rgba(255, 255, 255, 0.1);
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.subtitle {
  font-size: 1.2rem;
  font-weight: 300;
  opacity: 0.9;
}

main {
  padding: 3rem 0;
}

.toc-container {
  background: white;
  border-radius: 15px;
  padding: 3rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  border: 1px solid rgba(0, 0, 0, 0.05);
  position: relative;
  overflow: hidden;
}

.toc-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #3498db, #2c3e50);
}

.toc-title {
  font-size: 1.8rem;
  font-weight: 600;
  color: #2c3e50;
  margin-bottom: 2rem;
  text-align: center;
  border-bottom: 2px solid #ecf0f1;
  padding-bottom: 1rem;
}

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

.toc-item {
  margin-bottom: 1.5rem;
  padding: 1rem 0;
  border-bottom: 1px solid #ecf0f1;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.toc-item:last-child {
  border-bottom: none;
  margin-bottom: 0;
}

.toc-number {
  font-weight: 600;
  color: #3498db;
  margin-right: 1rem;
  min-width: 30px;
}

.toc-content {
  flex-grow: 1;
}

.toc-link {
  color: #2c3e50;
  text-decoration: none;
  font-weight: 500;
  font-size: 1.1rem;
  transition: color 0.3s ease;
}

.toc-link:hover {
  color: #3498db;
}

.toc-description {
  color: #666;
  font-size: 0.9rem;
  margin-top: 0.3rem;
  font-style: italic;
}

.toc-dots {
  flex-grow: 1;
  border-bottom: 2px dotted #ddd;
  margin: 0 1rem;
  height: 1px;
}

.toc-icon {
  margin-right: 0.5rem;
}

.loading-state {
  text-align: center;
  color: #666;
  font-style: italic;
  padding: 2rem;
}

.main-project {
  border-bottom: 2px solid #ecf0f1 !important;
  margin-bottom: 0.5rem !important;
}

.main-project-title {
  font-weight: 600;
  color: #2c3e50;
  cursor: default;
}

.sub-project {
  margin-left: 2rem;
  margin-bottom: 1rem !important;
  padding: 0.5rem 0 !important;
  border-bottom: 1px solid #f8f9fa !important;
}

.sub-project .toc-number {
  color: #7f8c8d;
  font-size: 0.9rem;
}

.sub-project-link {
  font-size: 1rem !important;
  color: #34495e;
}

.sub-project-link:hover {
  color: #3498db;
}

footer {
  background: #2c3e50;
  color: white;
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
}

@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }
  
  .nav-links {
    gap: 1rem;
  }
  
  .toc-container {
    padding: 2rem;
  }
  
  .container {
    padding: 0 15px;
  }
  
  .toc-item {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .toc-dots {
    display: none;
  }
}

/* Tag/Pill Styles */
.tag-list {
  margin-top: 1.5rem;
  margin-bottom: 1.5rem;
}

.pill {
  display: inline-block;
  padding: 0.4rem 0.8rem;
  background-color: #f8f9fa;
  border: 1px solid #e4e4e7;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 500;
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
  color: #374151;
  transition: all 0.2s ease;
}

.pill:hover {
  background-color: #e5e7eb;
  border-color: #d1d5db;
  transform: translateY(-1px);
}