:root {
  --color-primary: #1a3a52;
  --color-secondary: #2c5f7c;
  --color-accent: #c8a882;
  --color-text: #1f1f1f;
  --color-text-light: #4a4a4a;
  --color-text-muted: #6b7280;
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-bg-elevated: #ffffff;
  --color-border: #e5e7eb;
  --color-border-dark: #d1d5db;
  --color-link: #2563eb;
  --color-link-hover: #1d4ed8;

  --font-serif: 'Georgia', 'Times New Roman', serif;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;

  --max-width: 900px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  transform-origin: left;
  transform: scaleX(0);
  z-index: 9999;
  transition: transform 0.1s ease-out;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.site-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  color: white;
  padding: var(--spacing-3xl) 0 var(--spacing-2xl);
  text-align: center;
  box-shadow: var(--shadow-lg);
  margin-bottom: var(--spacing-3xl);
}

.site-title {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.02em;
}

.site-subtitle {
  font-size: 1.125rem;
  opacity: 0.9;
  font-weight: 400;
  letter-spacing: 0.02em;
}

.table-of-contents {
  position: sticky;
  top: 0;
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  box-shadow: var(--shadow-sm);
}

.toc-header {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.toc-toggle {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: var(--spacing-md);
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary);
  transition: var(--transition);
}

.toc-toggle:hover {
  background: var(--color-bg-alt);
}

.toc-icon {
  font-size: 1.25rem;
}

.toc-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease-out, opacity 0.3s ease;
  opacity: 0;
}

.toc-content.open {
  max-height: 80vh;
  overflow-y: auto;
  opacity: 1;
}

.toc-list {
  list-style: none;
  padding: var(--spacing-lg);
  max-width: var(--max-width);
  margin: 0 auto;
}

.toc-list li {
  margin-bottom: var(--spacing-sm);
}

.toc-list a {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: var(--transition);
  font-size: 0.9375rem;
}

.toc-list a:hover {
  background: var(--color-bg-alt);
  border-left-color: var(--color-primary);
  color: var(--color-primary);
}

.toc-list a.active {
  background: var(--color-bg-alt);
  border-left-color: var(--color-primary);
  color: var(--color-primary);
  font-weight: 600;
}

.main-content {
  padding-bottom: var(--spacing-3xl);
}

.article {
  background: var(--color-bg-elevated);
  padding: var(--spacing-3xl) var(--spacing-xl);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
}

.article-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 2px solid var(--color-border);
}

.article-title {
  font-family: var(--font-serif);
  font-size: 2rem;
  line-height: 1.3;
  color: var(--color-primary);
  margin-bottom: var(--spacing-lg);
  font-weight: 700;
}

.article-meta {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  font-style: italic;
}

.article-introduction {
  margin-bottom: var(--spacing-3xl);
  padding: var(--spacing-xl);
  background: linear-gradient(135deg, #f0f7ff 0%, #e0f0ff 100%);
  border-left: 4px solid var(--color-primary);
  border-radius: 4px;
}

.lead {
  font-size: 1.25rem;
  line-height: 1.7;
  color: var(--color-text);
}

article section {
  margin-bottom: var(--spacing-3xl);
}

h2 {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  line-height: 1.3;
  color: var(--color-primary);
  margin-top: var(--spacing-3xl);
  margin-bottom: var(--spacing-lg);
  font-weight: 700;
  scroll-margin-top: 80px;
}

h3 {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  line-height: 1.4;
  color: var(--color-secondary);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  font-weight: 600;
  scroll-margin-top: 80px;
}

p {
  margin-bottom: var(--spacing-lg);
  text-align: justify;
  hyphens: auto;
}

a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: var(--transition);
}

a:hover {
  color: var(--color-link-hover);
  text-decoration-thickness: 2px;
}

strong {
  font-weight: 600;
  color: var(--color-text);
}

ul, ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

li {
  margin-bottom: var(--spacing-sm);
}

.table-wrapper {
  overflow-x: auto;
  margin: var(--spacing-xl) 0;
  border-radius: 8px;
  box-shadow: var(--shadow-md);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
  background: white;
}

caption {
  font-weight: 600;
  text-align: left;
  padding: var(--spacing-md);
  background: var(--color-primary);
  color: white;
  font-size: 1rem;
}

thead {
  background: var(--color-bg-alt);
}

th {
  padding: var(--spacing-md);
  text-align: left;
  font-weight: 600;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-border-dark);
}

td {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
}

tbody tr {
  transition: var(--transition);
}

tbody tr:hover {
  background: var(--color-bg-alt);
}

.references {
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-xl);
  border-top: 2px solid var(--color-border);
}

.reference-list {
  counter-reset: reference-counter;
  list-style: none;
  padding-left: 0;
}

.reference-list li {
  counter-increment: reference-counter;
  position: relative;
  padding-left: 3rem;
  margin-bottom: var(--spacing-md);
  font-size: 0.9375rem;
  line-height: 1.6;
}

.reference-list li::before {
  content: "[" counter(reference-counter) "]";
  position: absolute;
  left: 0;
  font-weight: 600;
  color: var(--color-primary);
}

.site-footer {
  background: var(--color-primary);
  color: white;
  padding: var(--spacing-2xl) 0;
  text-align: center;
  margin-top: var(--spacing-3xl);
}

.site-footer p {
  margin-bottom: var(--spacing-sm);
  font-size: 0.9375rem;
  opacity: 0.9;
}

.scroll-to-top {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  z-index: 999;
}

.scroll-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-to-top:hover {
  background: var(--color-secondary);
  transform: translateY(-4px);
  box-shadow: 0 12px 20px -5px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
  html {
    font-size: 14px;
  }

  body {
    font-size: 1rem;
  }

  .site-header {
    padding: var(--spacing-xl) 0;
  }

  .site-title {
    font-size: 1.75rem;
  }

  .site-subtitle {
    font-size: 1rem;
  }

  .article {
    padding: var(--spacing-xl) var(--spacing-md);
  }

  .article-title {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.375rem;
  }

  h3 {
    font-size: 1.125rem;
  }

  .lead {
    font-size: 1.125rem;
  }

  table {
    font-size: 0.875rem;
  }

  th, td {
    padding: var(--spacing-sm);
  }

  .scroll-to-top {
    bottom: var(--spacing-md);
    right: var(--spacing-md);
    width: 40px;
    height: 40px;
    font-size: 1.25rem;
  }

  p {
    text-align: left;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }

  .article {
    padding: var(--spacing-lg) var(--spacing-sm);
  }

  .article-introduction {
    padding: var(--spacing-md);
  }
}

@media print {
  .progress-bar,
  .table-of-contents,
  .scroll-to-top {
    display: none;
  }

  .article {
    box-shadow: none;
  }

  body {
    font-size: 12pt;
  }

  h2 {
    page-break-after: avoid;
  }

  table {
    page-break-inside: avoid;
  }
}