:root {
  --ocean-dark: #0f1419;
  --ocean-deep: #1a2332;
  --ocean-medium: #2d3748;
  --ocean-light: #4a5568;
  --ocean-accent: #3182ce;
  --ocean-text: #e2e8f0;
  --ocean-text-muted: #a0aec0;
  --ocean-border: #2d3748;
  --header-height: 60px;
}

html {
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: var(--ocean-text);
  background: linear-gradient(135deg, var(--ocean-dark) 0%, var(--ocean-deep) 100%);
  min-height: 100vh;
  padding-top: var(--header-height);
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

.header {
  font-family: "JetBrains Mono", monospace;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(15, 20, 25, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--ocean-border);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: 1440px;
  padding: 0 2rem;
}

.header__logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--ocean-accent);
  text-decoration: none;
}

.header__right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.header__lang {
  display: flex;
  gap: 0.5rem;
}

.header__lang-item {
  color: var(--ocean-text-muted);
  text-decoration: none;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  transition: all 0.2s ease;
  font-size: 0.9rem;
}

.header__lang-item:hover {
  color: var(--ocean-text);
  background: var(--ocean-medium);
}

.header__links {
  display: flex;
  gap: 0.5rem;
}

.header__link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 6px;
  transition: all 0.2s ease;
}

.header__link:hover {
  background: var(--ocean-medium);
}

.header__link-icon {
  width: 18px;
  height: 18px;
  filter: invert(1) opacity(0.7);
  transition: opacity 0.2s ease;
}

.header__link:hover .header__link-icon {
  opacity: 1;
}

.markdown-body {
  color: var(--ocean-text);
}

.markdown-body h1 {
  font-size: 2.5rem;
  color: var(--ocean-accent);
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--ocean-border);
  padding-bottom: 0.5rem;
  font-weight: bold;
}

.markdown-body h2 {
  font-size: 1.8rem;
  color: var(--ocean-text);
  margin: 2rem 0 1rem 0;
  border-bottom: 1px solid var(--ocean-border);
  padding-bottom: 0.3rem;
  font-weight: bold;
}

.markdown-body h3 {
  font-size: 1.3rem;
  color: var(--ocean-text);
  margin: 1.5rem 0 0.5rem 0;
  font-weight: bold;
}

.markdown-body p {
  margin-bottom: 1rem;
  color: var(--ocean-text-muted);
}

.markdown-body strong {
  color: var(--ocean-text);
  font-weight: 600;
}

.markdown-body a {
  color: var(--ocean-accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.markdown-body a:hover {
  border-bottom-color: var(--ocean-accent);
}

.markdown-body ul {
  margin: 1rem 0;
  padding-left: 1.5rem;
  list-style-type: disc;
}

.markdown-body li {
  margin-bottom: 0.5rem;
  color: var(--ocean-text-muted);
}

.markdown-body hr {
  border: none;
  height: 1px;
  background: var(--ocean-border);
  margin: 2rem 0;
}

.markdown-body em {
  color: var(--ocean-text-muted);
  font-style: italic;
}

.footer {
  height: 2rem;
  background: var(--ocean-deep);
  border-top: 1px solid var(--ocean-border);
}

@media (max-width: 768px) {
  .header {
    padding: 0 1rem;
  }

  .header__logo {
    font-size: 1.3rem;
  }

  .header__right {
    gap: 1rem;
  }

  main {
    padding: 1.5rem 1rem;
  }

  .markdown-body h1 {
    font-size: 2rem;
  }

  .markdown-body h2 {
    font-size: 1.5rem;
  }
}

@media (max-width: 480px) {
  .header {
    padding: 0 0.5rem;
  }

  .header__lang-item {
    font-size: 0.8rem;
    padding: 0.2rem 0.4rem;
  }

  main {
    padding: 1rem 0.5rem;
  }
}