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

:root {
  --color-primary: #0f4c75;
  --color-secondary: #1b262c;
  --color-accent: #bbe1fa;
  --color-bg: #ffffff;
  --color-surface: #f0f7ff;
  --color-text: #1b262c;
  --color-text-muted: #6b7b8d;
  --color-border: #d1dce6;
  --font-main: 'Verdana', 'Geneva', 'Tahoma', sans-serif;
  --max-width: 1100px;
  --radius: 4px;
  --radius-sm: 2px;
  --radius-lg: 8px;
  --spacing-unit: 8px;
}

body {
  font-family: var(--font-main);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image: linear-gradient(180deg, var(--color-bg) 0%, var(--color-surface) 100%);
  background-attachment: fixed;
  min-height: 100vh;
  display: grid;
  grid-template-rows: auto 1fr auto;
  transition: background-color 0.2s ease;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: calc(var(--spacing-unit) * 2);
  color: var(--color-secondary);
  letter-spacing: -0.02em;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: calc(var(--spacing-unit) * 3);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 2px 4px rgba(15, 76, 117, 0.1);
}

h2 {
  font-size: 2rem;
  border-bottom: 2px solid var(--color-border);
  padding-bottom: calc(var(--spacing-unit) * 1.5);
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.25rem;
}

h5 {
  font-size: 1.125rem;
}

h6 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

p {
  margin-bottom: calc(var(--spacing-unit) * 2);
  max-width: 70ch;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

a:hover {
  color: var(--color-secondary);
  border-bottom-color: var(--color-accent);
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

strong {
  font-weight: 700;
  color: var(--color-secondary);
}

em {
  font-style: italic;
  color: var(--color-text);
}

blockquote {
  margin: calc(var(--spacing-unit) * 3) 0;
  padding: calc(var(--spacing-unit) * 2) calc(var(--spacing-unit) * 3);
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-bg) 100%);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: 0 2px 8px rgba(15, 76, 117, 0.08);
  font-style: italic;
  color: var(--color-text-muted);
}

::selection {
  background-color: var(--color-accent);
  color: var(--color-secondary);
}

.site-header {
  background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-primary) 100%);
  color: var(--color-bg);
  padding: calc(var(--spacing-unit) * 3) 0;
  box-shadow: 0 4px 12px rgba(15, 76, 117, 0.15), 0 2px 4px rgba(15, 76, 117, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
}

.site-header h1 {
  color: var(--color-bg);
  background: none;
  -webkit-text-fill-color: var(--color-bg);
  margin: 0;
  font-size: 1.75rem;
  letter-spacing: 0.02em;
}

.site-nav {
  margin-top: calc(var(--spacing-unit) * 2);
}

.site-nav ul {
  list-style: none;
  display: flex;
  gap: calc(var(--spacing-unit) * 3);
  flex-wrap: wrap;
}

.site-nav a {
  color: var(--color-accent);
  border-bottom: 2px solid transparent;
  padding-bottom: calc(var(--spacing-unit) * 0.5);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.875rem;
  letter-spacing: 0.05em;
}

.site-nav a:hover {
  color: var(--color-bg);
  border-bottom-color: var(--color-bg);
}

.site-main {
  padding: calc(var(--spacing-unit) * 4) 0;
}

.site-footer {
  background-color: var(--color-secondary);
  color: var(--color-accent);
  padding: calc(var(--spacing-unit) * 4) 0;
  margin-top: calc(var(--spacing-unit) * 8);
  border-top: 4px solid var(--color-primary);
  box-shadow: 0 -4px 12px rgba(15, 76, 117, 0.1);
}

.site-footer a {
  color: var(--color-accent);
  border-bottom-color: transparent;
}

.site-footer a:hover {
  color: var(--color-bg);
  border-bottom-color: var(--color-bg);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 calc(var(--spacing-unit) * 2);
}

.breadcrumbs {
  display: flex;
  gap: calc(var(--spacing-unit) * 1.5);
  align-items: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: calc(var(--spacing-unit) * 3);
  padding: calc(var(--spacing-unit) * 1.5);
  background-color: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(15, 76, 117, 0.06);
  flex-wrap: wrap;
}

.breadcrumbs a {
  color: var(--color-primary);
  transition: color 0.2s ease, background-color 0.2s ease;
  padding: calc(var(--spacing-unit) * 0.5) calc(var(--spacing-unit) * 1);
  border-radius: var(--radius-sm);
}

.breadcrumbs a:hover {
  background-color: var(--color-accent);
  color: var(--color-secondary);
}

.breadcrumbs span {
  color: var(--color-text-muted);
}

.card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: calc(var(--spacing-unit) * 3);
  margin-bottom: calc(var(--spacing-unit) * 3);
  box-shadow: 0 2px 8px rgba(15, 76, 117, 0.08), 0 1px 3px rgba(15, 76, 117, 0.04);
  transition: box-shadow 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.card:hover {
  box-shadow: 0 8px 24px rgba(15, 76, 117, 0.12), 0 4px 8px rgba(15, 76, 117, 0.08);
  border-color: var(--color-accent);
  transform: translateY(-2px);
}

.card h2, .card h3, .card h4 {
  margin-top: 0;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: calc(var(--spacing-unit) * 3) 0;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(15, 76, 117, 0.06);
}

table thead {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  color: var(--color-bg);
}

table th {
  padding: calc(var(--spacing-unit) * 2);
  text-align: left;
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.875rem;
  letter-spacing: 0.05em;
}

table td {
  padding: calc(var(--spacing-unit) * 2);
  border-bottom: 1px solid var(--color-border);
  transition: background-color 0.2s ease;
}

table tbody tr:nth-child(even) {
  background-color: var(--color-surface);
}

table tbody tr:hover {
  background-color: var(--color-accent);
}

table tbody tr:last-child td {
  border-bottom: none;
}

details {
  margin: calc(var(--spacing-unit) * 2) 0;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(15, 76, 117, 0.06);
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
}

details:hover {
  border-color: var(--color-accent);
  box-shadow: 0 4px 12px rgba(15, 76, 117, 0.1);
}

details[open] {
  border-color: var(--color-primary);
}

summary {
  padding: calc(var(--spacing-unit) * 2);
  cursor: pointer;
  font-weight: 700;
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-bg) 100%);
  user-select: none;
  list-style: none;
  position: relative;
  transition: background-color 0.2s ease, color 0.2s ease;
}

summary::-webkit-details-marker {
  display: none;
}

summary::before {
  content: '▸';
  display: inline-block;
  margin-right: calc(var(--spacing-unit) * 1.5);
  transition: transform 0.2s ease;
  color: var(--color-primary);
  font-size: 1.2em;
}

details[open] summary::before {
  transform: rotate(90deg);
}

summary:hover {
  background-color: var(--color-accent);
  color: var(--color-secondary);
}

summary:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: -2px;
}

details > *:not(summary) {
  padding: calc(var(--spacing-unit) * 2);
  animation: slideDown 0.2s ease;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

ul, ol {
  margin-bottom: calc(var(--spacing-unit) * 2);
  padding-left: calc(var(--spacing-unit) * 4);
}

li {
  margin-bottom: calc(var(--spacing-unit) * 1);
}

code {
  background-color: var(--color-surface);
  padding: calc(var(--spacing-unit) * 0.5) calc(var(--spacing-unit) * 1);
  border-radius: var(--radius-sm);
  font-family: 'Courier New', monospace;
  font-size: 0.9em;
  color: var(--color-primary);
  border: 1px solid var(--color-border);
}

pre {
  background-color: var(--color-surface);
  padding: calc(var(--spacing-unit) * 2);
  border-radius: var(--radius);
  overflow-x: auto;
  margin: calc(var(--spacing-unit) * 2) 0;
  border: 1px solid var(--color-border);
  box-shadow: 0 2px 4px rgba(15, 76, 117, 0.06);
}

pre code {
  background: none;
  padding: 0;
  border: none;
}

@media (min-width: 768px) {
  h1 {
    font-size: 3rem;
  }

  h2 {
    font-size: 2.25rem;
  }

  h3 {
    font-size: 1.75rem;
  }

  .site-header {
    padding: calc(var(--spacing-unit) * 4) 0;
  }

  .site-header h1 {
    font-size: 2.25rem;
  }

  .site-nav {
    margin-top: calc(var(--spacing-unit) * 2.5);
  }

  .site-nav ul {
    gap: calc(var(--spacing-unit) * 4);
  }

  .site-main {
    padding: calc(var(--spacing-unit) * 6) 0;
  }

  .container {
    padding: 0 calc(var(--spacing-unit) * 3);
  }

  .card {
    padding: calc(var(--spacing-unit) * 4);
  }

  table th, table td {
    padding: calc(var(--spacing-unit) * 2.5);
  }
}

@media (min-width: 1024px) {
  body {
    font-size: 18px;
  }

  h1 {
    font-size: 3.5rem;
  }

  h2 {
    font-size: 2.5rem;
  }

  .site-header {
    padding: calc(var(--spacing-unit) * 5) 0;
  }

  .site-header h1 {
    font-size: 2.5rem;
  }

  .site-main {
    padding: calc(var(--spacing-unit) * 8) 0;
  }

  .container {
    padding: 0 calc(var(--spacing-unit) * 4);
  }

  .site-footer {
    padding: calc(var(--spacing-unit) * 6) 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  details > *:not(summary) {
    animation: none;
  }

  .card:hover {
    transform: none;
  }
}

@media print {
  .site-header,
  .site-nav,
  .site-footer,
  .breadcrumbs {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .container {
    max-width: 100%;
    padding: 0;
  }

  .card {
    box-shadow: none;
    border: 1px solid #ccc;
    page-break-inside: avoid;
  }

  a {
    color: black;
    text-decoration: underline;
  }

  h1, h2, h3, h4, h5, h6 {
    page-break-after: avoid;
  }
}