:root {
  --gray-100: #f3f4f6;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  
  --font-serif: 'Noto Serif SC', 'Songti SC', 'SimSun', Georgia, serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

body {
  font-family: var(--font-serif);
  background-color: #ffffff;
  color: var(--gray-900);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.page-padding {
  padding: 1.5rem;
}

@media (min-width: 768px) {
  .page-padding {
    padding: 2rem;
  }
}

.header {
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  max-width: 1152px; /* max-w-base estimate */
}

.logo-group {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  text-decoration: none;
  border-radius: 0.125rem;
}

.logo-icon {
  display: block;
  color: var(--gray-400);
  transition: color 0.2s;
}

.logo-group:hover .logo-icon {
  color: var(--gray-500);
}

.logo-text {
  font-family: var(--font-serif);
  font-size: 1rem;
  letter-spacing: -0.3px;
  color: var(--gray-900);
}

.logo-text-muted {
  color: var(--gray-400);
  transition: color 0.2s;
}

.logo-group:hover .logo-text-muted {
  color: var(--gray-500);
}

.main-container {
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  max-width: 1152px;
  padding-top: 6rem;
}

.sections-container {
  display: flex;
  flex-direction: column;
  gap: 8rem; /* space-y-32 */
}

.intro-section {
  display: grid;
  width: 100%;
  gap: 0.25rem;
  border-bottom: 1px solid var(--gray-100);
  padding-bottom: 2rem;
  margin-bottom: 5rem;
}

@media (min-width: 768px) {
  .intro-section {
    border-bottom: none;
    padding-bottom: 1.5rem;
    margin-bottom: 8rem;
  }
}

@media (min-width: 1024px) {
  .intro-section {
    grid-template-columns: 380px 1fr;
    gap: 2rem;
  }
}

.intro-left {
  display: flex;
  align-items: baseline;
}

.intro-title-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.index-badge {
  display: none;
  height: 1rem;
  width: 1.5rem;
  transform: translateY(-1px);
  place-items: center;
  border-radius: 0.125rem;
  border: 1px solid var(--gray-100);
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--gray-900);
}

@media (min-width: 1024px) {
  .index-badge {
    display: grid;
  }
}

.section-title {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  letter-spacing: -0.025em;
  font-weight: 500;
  color: var(--gray-900);
}

@media (min-width: 768px) {
  .section-title {
    font-size: 1.5rem;
  }
}

.title-line {
  display: none;
  margin-left: 1rem;
  margin-right: 1rem;
  height: 1px;
  width: auto;
  flex-grow: 1;
  flex-shrink: 0;
  transform: translateY(3px);
  background-color: var(--gray-100);
}

@media (min-width: 1024px) {
  .title-line {
    display: block;
  }
}

.section-desc {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  letter-spacing: -0.025em;
  color: var(--gray-700);
  text-wrap: balance;
  line-height: 1.4;
}

@media (min-width: 1024px) {
  .section-desc {
    font-size: 1.5rem;
  }
}

/* Category Sections */
.category-wrapper {
  display: grid;
  gap: 0.25rem;
  scroll-margin-top: 1.5rem;
}

@media (min-width: 1024px) {
  .category-wrapper {
    grid-template-columns: 380px 1fr;
    gap: 2rem;
  }
}

.category-left {
  display: flex;
  height: max-content;
  align-items: baseline;
  top: 1rem;
}

@media (min-width: 1024px) {
  .category-left {
    position: sticky;
  }
}

.category-link {
  display: flex;
  align-items: center;
  gap: 1rem;
  border-radius: 0.125rem;
  text-decoration: none;
}

.category-right {
  /* content column */
}

.terms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 2rem;
  margin-top: 2.5rem;
}

@media (min-width: 1024px) {
  .terms-grid {
    margin-top: 3rem;
  }
}

.term-block {
  break-inside: avoid;
}

.term-name {
  display: inline-block;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  font-family: var(--font-serif);
  font-weight: 700;
  letter-spacing: 0.025em;
  color: var(--gray-900);
}

.term-desc {
  font-size: 0.875rem;
  line-height: 1.5;
  letter-spacing: 0.025em;
  color: var(--gray-800);
}

.footer {
  margin-top: 6rem;
  border-top: 1px solid var(--gray-100);
  padding-top: 2rem;
  padding-bottom: 4rem;
  font-size: 0.875rem;
  color: var(--gray-500);
}

html {
  scroll-behavior: smooth;
}