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

:root {
  --color-primary: #475569;
  --color-secondary: #1e293b;
  --color-accent: #38bdf8;
  --color-bg: #ffffff;
  --color-surface: #f8fafc;
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --font-main: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --max-width: 1100px;
  --radius: 16px;
  --radius-sm: 8px;
  --radius-lg: 24px;
  --shadow-soft: inset 0 2px 4px rgba(15, 23, 42, 0.04);
  --shadow-elevation-1: 0 2px 8px rgba(71, 85, 105, 0.08), 0 1px 3px rgba(71, 85, 105, 0.04);
  --shadow-elevation-2: 0 4px 16px rgba(71, 85, 105, 0.12), 0 2px 6px rgba(71, 85, 105, 0.06);
  --shadow-elevation-3: 0 8px 24px rgba(71, 85, 105, 0.16), 0 4px 12px rgba(71, 85, 105, 0.08);
  --gradient-warm: linear-gradient(135deg, #f8fafc 0%, #ffffff 50%, #f8fafc 100%);
  --gradient-subtle: linear-gradient(180deg, rgba(56, 189, 248, 0.03) 0%, rgba(71, 85, 105, 0.02) 100%);
}

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

body {
  font-family: var(--font-main);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--gradient-warm);
  background-attachment: fixed;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-secondary);
  margin-bottom: 1rem;
}

h1 {
  font-size: 2.25rem;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 1.875rem;
  letter-spacing: -0.01em;
  color: var(--color-primary);
}

h3 {
  font-size: 1.5rem;
  color: var(--color-primary);
}

h4 {
  font-size: 1.25rem;
}

h5 {
  font-size: 1.125rem;
}

h6 {
  font-size: 1rem;
  font-weight: 600;
}

p {
  margin-bottom: 1.25rem;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
  border-radius: var(--radius-sm);
}

a:hover {
  color: var(--color-secondary);
  text-decoration: underline;
}

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

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

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

blockquote {
  margin: 1.5rem 0;
  padding: 1.25rem 1.5rem;
  background: var(--gradient-subtle);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  color: var(--color-text-muted);
  font-style: italic;
}

blockquote p:last-child {
  margin-bottom: 0;
}

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

.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-elevation-1);
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(8px);
  background: rgba(255, 255, 255, 0.95);
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  gap: 2rem;
}

.site-nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.site-nav a {
  padding: 0.625rem 1.125rem;
  color: var(--color-text-muted);
  font-weight: 500;
  border-radius: var(--radius);
  transition: color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
}

.site-nav a:hover {
  color: var(--color-accent);
  background: var(--color-surface);
  text-decoration: none;
  box-shadow: var(--shadow-soft);
}

.site-nav a:focus-visible {
  background: var(--color-surface);
  box-shadow: 0 0 0 2px var(--color-accent);
}

.site-main {
  flex: 1;
  padding: 2rem 0;
}

.site-footer {
  background: var(--color-secondary);
  color: var(--color-surface);
  padding: 2.5rem 0 1.5rem;
  margin-top: 4rem;
  border-top-left-radius: var(--radius-lg);
  border-top-right-radius: var(--radius-lg);
  box-shadow: var(--shadow-elevation-3);
}

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

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

.site-footer p {
  color: var(--color-text-muted);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding: 0.75rem 1rem;
  background: var(--color-surface);
  border-radius: var(--radius);
  font-size: 0.875rem;
  box-shadow: var(--shadow-soft);
}

.breadcrumbs a {
  color: var(--color-text-muted);
  padding: 0.25rem 0.5rem;
}

.breadcrumbs a:hover {
  color: var(--color-accent);
  background: var(--color-bg);
  border-radius: var(--radius-sm);
}

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

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-elevation-1);
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
  background: var(--gradient-subtle);
}

.card:hover {
  box-shadow: var(--shadow-elevation-2);
  border-color: var(--color-accent);
}

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

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  background: var(--color-bg);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-elevation-1);
}

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

table th {
  padding: 1rem 1.25rem;
  text-align: left;
  font-weight: 600;
  letter-spacing: 0.02em;
}

table td {
  padding: 0.875rem 1.25rem;
  border-top: 1px solid var(--color-border);
}

table tbody tr {
  transition: background-color 0.2s ease;
}

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

table tbody tr:hover {
  background: rgba(56, 189, 248, 0.05);
  box-shadow: var(--shadow-soft);
}

details {
  margin: 1.25rem 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-elevation-1);
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
}

details[open] {
  box-shadow: var(--shadow-elevation-2);
  border-color: var(--color-accent);
}

summary {
  padding: 1.125rem 1.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--color-primary);
  background: var(--gradient-subtle);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background-color 0.2s ease, color 0.2s ease;
  user-select: none;
}

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

summary::after {
  content: '+';
  font-size: 1.5rem;
  font-weight: 300;
  color: var(--color-accent);
  transition: transform 0.2s ease;
  line-height: 1;
}

details[open] summary::after {
  transform: rotate(45deg);
}

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

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

details div {
  padding: 1.25rem 1.5rem;
  border-top: 1px solid var(--color-border);
}

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

  h2 {
    font-size: 2.25rem;
  }

  h3 {
    font-size: 1.75rem;
  }

  .site-header .container {
    padding: 1.25rem 2rem;
  }

  .site-main {
    padding: 3rem 0;
  }

  .site-footer {
    padding: 3rem 0 2rem;
  }

  .container {
    padding: 0 2rem;
  }

  .site-nav {
    gap: 1rem;
  }

  .site-nav a {
    padding: 0.75rem 1.5rem;
  }

  .card {
    padding: 2.25rem;
  }

  table th,
  table td {
    padding: 1rem 1.5rem;
  }
}

@media (min-width: 1024px) {
  h1 {
    font-size: 3.5rem;
  }

  .site-main {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .card {
    padding: 2.5rem;
  }

  details div {
    padding: 1.5rem 2rem;
  }

  summary {
    padding: 1.25rem 2rem;
  }
}

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

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

  .site-main {
    padding: 0;
  }

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

  .card {
    box-shadow: none;
    border: 1px solid var(--color-border);
    page-break-inside: avoid;
  }

  a {
    color: var(--color-text);
    text-decoration: underline;
  }

  details {
    border: 1px solid var(--color-border);
  }

  details summary::after {
    display: none;
  }

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